Przedwczesne zagnieżdżenie łożyska

Przedwczesne zagnieżdżenie łożyska
Epidemiologia

Przedwczesne zagnieżdżenie łożyska (placenta previa) to poważne powikłanie położnicze, charakteryzujące się lokalizacją tkanki łożyskowej nad wewnętrznym ujściem szyjki macicy, co wiąże się z koniecznością cięcia cesarskiego oraz ryzykiem ciężkiego krwawienia przedporodowego, porodu przedwczesnego i krwotoku poporodowego. Częstość występowania łożyska przodującego waha się globalnie od 0,3% do 2% ciąż w trzecim trymestrze, z najwyższą częstością w Chinach kontynentalnych (12,2 na 1000 ciąż) i najniższą w Afryce Subsaharyjskiej (2,7 na 1000 ciąż). Czynniki ryzyka obejmują wcześniejsze cięcia cesarskie (ryzyko wzrasta do 3,7% po 5 cięciach), zaawansowany wiek matki (do 5% po 40 roku życia), wcześniejsze łożysko przodujące, wielorództwo, wcześniejsze poronienia (OR 1,77 dla samoistnych), krótki odstęp między ciążami, mięśniaki macicy (OR 6,33), palenie tytoniu, ciąże mnogie oraz techniki wspomaganego rozrodu. Istotnym powikłaniem jest zespół łożyska wrośniętego (PAS), występujący u około 10% pacjentek z łożyskiem przodującym, z ryzykiem wzrastającym do 67% po pięciu lub więcej cięciach cesarskich.

Epidemiologia przedwczesnego zagnieżdżenia łożyska

Częstotliwość występowania na świecie
Zmiany w częstoliwości występowania w czasie
Czynniki ryzyka przedwczesnego zagnieżdżenia łożyska
Przedwczesne zagnieżdżenie łożyska z zespołem placenta accreta

Diagnostyka i nadzór nad przedwczesnym zagnieżdżeniem łożyska

Metody diagnostyczne
Protokoły nadzoru i obserwacji
Heterogeniczność w danych epidemiologicznych
Komplikacje i nadzór w przypadku krwawienia
Znaczenie badań naukowych i nadzoru klinicznego
Kolejne rozdziały

Epidemiologia przedwczesnego zagnieżdżenia łożyska

Przedwczesne zagnieżdżenie łożyska (placenta previa) to stan, w którym tkanka łożyskowa rozciąga się nad wewnętrznym ujściem szyjki macicy. Konsekwencje tego stanu obejmują konieczność wykonania cięcia cesarskiego oraz ryzyko wystąpienia ciężkiego krwawienia przedporodowego, porodu przedwczesnego i krwotoku poporodowego.¹² Jest to jedno z poważnych powikłań położniczych, które w znaczącym stopniu przyczynia się do zachorowalności i umieralności zarówno matki, jak i płodu.³⁴

Częstotliwość występowania na świecie

Częstość występowania łożyska przodującego waha się w zależności od regionu geograficznego i czasu trwania ciąży. W przeglądach systematycznych, łączna częstość występowania przedwczesnego zagnieżdżenia łożyska wynosi około 4-5 na 1000 porodów, ale różni się na całym świecie.⁵⁶ Według niektórych badań, częstość występowania waha się od 0,3% do 2% ciąż w trzecim trymestrze.⁷⁸

W dużym, opartym na populacji badaniu przeprowadzonym w USA w latach 1989-1997, stwierdzono częstość występowania 2,8 na 1000 żywych urodzeń.⁹ Inne źródła podają, że łożysko przodujące występuje w przybliżeniu w 1 na 200 ciąż (0,5%) w USA.¹⁰¹¹¹² W badaniu przeprowadzonym w Arabii Saudyjskiej odnotowano częstość występowania 4,1 na 1000 porodów.¹³

Wyraźne są różnice geograficzne w częstości występowania łożyska przodującego:¹⁴¹⁵

Afryka Subsaharyjska: 2,7 na 1000 ciąż (najniższa na świecie)
Afryka Północna: 6,4 na 1000 ciąż
Europa: 3,6 na 1000 ciąż
Ameryka Północna: 2,9 na 1000 ciąż
Ameryka Łacińska: 5,1 na 1000 ciąż
Bliski Wschód: 4,2-7,3 na 1000 ciąż
Australia: 9,5 na 1000 ciąż
Chiny kontynentalne: 12,2 na 1000 ciąż (najwyższa na świecie)

¹⁶

Meta-analiza badań z Chin wskazała, że łączna częstość występowania łożyska przodującego wśród porodów wyniosła 1,24% (95% CI, 1,12-1,36) w Chinach kontynentalnych w latach 1965-2015.¹⁷ Rozkład geograficzny łożyska przodującego był nierówny w Chinach kontynentalnych, z częstością występowania od 0,93% do 2,01% w różnych regionach.¹⁸

Zmiany w częstoliwości występowania w czasie

Badania sugerują, że częstość występowania łożyska przodującego wzrasta z powodu rosnącej liczby cięć cesarskich.¹⁹²⁰ W przypadku Chin, po wprowadzeniu polityki dwojga dzieci, częstość występowania łożyska przodującego znacząco wzrosła z 1,25% (95% CI = 1,16, 1,34) do 4,12% (95% CI = 3,33, 4,91).²¹

Zauważono również, że częstość występowania jest znacznie wyższa w 20. tygodniu ciąży niż w momencie porodu, ponieważ większość przypadków zidentyfikowanych wcześnie w ciąży ustępuje przed porodem. W jednym z badań, 11% pacjentek poddawanych rutynowemu przezpochwowemu badaniu długości szyjki macicy w okolicach tego wieku ciążowego miało łożysko przodujące lub krawędź łożyska w odległości mniejszej niż 2 cm od wewnętrznego ujścia.²²²³

Prawie 90% łożysk określanych jako „nisko położone” ostatecznie ustąpi do trzeciego trymestru w wyniku tak zwanej „migracji łożyska”.²⁴²⁵ Szanse na ustąpienie łożyska przodującego są bezpośrednio związane z wiekiem ciążowym w momencie diagnozy ultrasonograficznej: utrzymuje się u 12% zdiagnozowanych w 15-19 tygodniu; 34% w 20-23 tygodniu; 39% w 24-27 tygodniu; 62% w 28-31 tygodniu i 73% w 32-35 tygodniu.²⁶

Czynniki ryzyka przedwczesnego zagnieżdżenia łożyska

Zidentyfikowano kilka kluczowych czynników ryzyka związanych z występowaniem łożyska przodującego:²⁷²⁸²⁹

Wcześniejsze cięcie cesarskie: Ryzyko łożyska przodującego wzrasta 1,5-5-krotnie u kobiet po cięciu cesarskim.³⁰ Meta-analiza wykazała, że częstość łożyska przodującego zwiększa się wraz z rosnącą liczbą cięć cesarskich, osiągając 1% po 1 cięciu cesarskim, 2,8% po 3 cięciach cesarskich i nawet 3,7% po 5 cięciach cesarskich.³¹³²
Zaawansowany wiek matki: Częstość występowania łożyska przodującego po 35 roku życia wynosi około 2%. Dalszy wzrost do 5% obserwuje się po 40 roku życia, co stanowi 9-krotny wzrost w porównaniu z kobietami poniżej 20 roku życia.³³ W badaniu przeprowadzonym w Etiopii wykazano, że szansa na rozwój łożyska przodującego była 4,45 razy większa wśród ciężarnych w wieku 35 lat i starszych w porównaniu z kobietami poniżej 35 lat.³⁴
Wcześniejsze łożysko przodujące: Historia łożyska przodującego w poprzedniej ciąży zwiększa ryzyko jego ponownego wystąpienia.³⁵³⁶
Wielorództwo: Większa liczba przebytych ciąż zwiększa ryzyko łożyska przodującego.³⁷³⁸
Wcześniejsze poronienia: Meta-analiza wykazała znaczący związek między wcześniejszymi samoistnym poronieniami a łożyskiem przodującym (OR 1,77; 95% CI: 1,60, 1,94) oraz między wcześniejszymi sztucznymi poronieniami a łożyskiem przodującym (OR 1,36; 95% CI: 1,02, 1,69).³⁹ W badaniu etiopskim stwierdzono, że szansa rozwoju łożyska przodującego była 5,49 razy większa wśród matek z wcześniejszymi poronieniami w porównaniu z kobietami bez wcześniejszych poronień.⁴⁰
Krótki odstęp między ciążami: Badanie wykazało, że szansa rozwoju łożyska przodującego była 1,89 razy większa wśród ciężarnych z odstępem między ciążami krótszym niż 24 miesiące w porównaniu z kobietami o odstępie 24 miesiące i dłuższym.⁴¹
Mięśniaki macicy: Szansa rozwoju łożyska przodującego była 6,33 razy większa wśród kobiet z mięśniakami macicy w porównaniu z kobietami bez mięśniaków.⁴²⁴³
Palenie tytoniu: Wykazano przekonujący związek między paleniem a zwiększonym ryzykiem łożyska przodującego, z zależnym od dawki wzrostem ryzyka.⁴⁴
Ciąża mnoga: Ciąże mnogie są czynnikiem ryzyka łożyska przodującego.⁴⁵⁴⁶
Techniki wspomaganego rozrodu: Ciąże powstałe w wyniku technik wspomaganego rozrodu mają wyższe ryzyko łożyska przodującego.⁴⁷⁴⁸

Przedwczesne zagnieżdżenie łożyska z zespołem placenta accreta

Szczególnie istotnym aspektem epidemiologii łożyska przodującego jest jego związek z zespołem łożyska wrośniętego (placenta accreta spectrum, PAS). Według przeglądu systematycznego i meta-analizy: ⁴⁹⁵⁰

Mediana częstości występowania łożyska przodującego wynosiła 0,56% (IQR 0,39-1,24)
Mediana częstości występowania łożyska przodującego z PAS wynosiła 0,07% (IQR 0,05-0,16)
Częstość występowania PAS u kobiet z łożyskiem przodującym wynosiła 11,10% (IQR 7,65-17,35)

⁵¹⁵²

Łożysko wrośnięte (placenta accreta) występuje u około 10% pacjentek z łożyskiem przodującym.⁵³ Duże wieloośrodkowe badanie kohortowe w USA wykazało, że dla kobiet z łożyskiem przodującym i wcześniejszym cięciem cesarskim, ryzyko PAS wynosiło 3%, 11%, 40%, 61% i 67% odpowiednio dla pierwszego, drugiego, trzeciego, czwartego i piątego lub większej liczby cięć cesarskich.⁵⁴

Krajowe badanie kliniczno-kontrolne wykorzystujące brytyjski system nadzoru położniczego wykazało, że częstość występowania PAS wzrasta z 1,7 na 10 000 urodzeń ogółem do 577 na 10 000 urodzeń u kobiet zarówno po wcześniejszym cięciu cesarskim, jak i z łożyskiem przodującym.⁵⁵⁵⁶

Diagnostyka i nadzór nad przedwczesnym zagnieżdżeniem łożyska

Odpowiedni nadzór i wczesna diagnostyka łożyska przodującego mają kluczowe znaczenie dla minimalizacji ryzyka powikłań zarówno dla matki, jak i płodu.⁵⁷

Metody diagnostyczne

Łożysko przodujące jest zazwyczaj diagnozowane za pomocą badania ultrasonograficznego, które może być przeprowadzone podczas rutynowej wizyty prenatalnej lub po epizodzie krwawienia z pochwy.⁵⁸ Większość przypadków łożyska przodującego jest diagnozowana podczas badania ultrasonograficznego w drugim trymestrze ciąży.⁵⁹

Metody obrazowania stosowane do oceny lokalizacji łożyska obejmują:⁶⁰

Ultrasonografia położnicza:
- Przezbrzuszna (TAS): potwierdza łożysko przodujące w 96% przypadków
- Przezpochwowa (TVS): jest bezpieczna i przewyższa ultrasonografię przezbrzuszną; jest metodą z wyboru, o czułości 95% i swoistości 93%⁶¹⁶²
- Przezkroczowa
Rezonans magnetyczny (MRI): używany w bardziej skomplikowanych przypadkach, szczególnie przy podejrzeniu współistniejącego łożyska wrośniętego

Diagnoza łożyska przodującego opiera się na identyfikacji echogennej jednorodnej tkanki łożyskowej nad wewnętrznym ujściem szyjki macicy.⁶³ Ocena lokalizacji łożyska w badaniu anatomicznym płodu w drugim trymestrze jest kluczowym elementem badania ultrasonograficznego, zgodnie z zaleceniami różnych krajowych i międzynarodowych wytycznych.⁶⁴

Protokoły nadzoru i obserwacji

Rutynowa ultrasonografia w pierwszym i drugim trymestrze ciąży zapewnia wczesną identyfikację łożyska przodującego. Ważne jest, aby zdawać sobie sprawę, że im wcześniejsza diagnoza łożyska przodującego, tym bardziej prawdopodobne jest jej ustąpienie przed porodem w wyniku „migracji łożyska”.⁶⁵

Zaleca się kontrolne badanie ultrasonograficzne w 28-32 tygodniu ciąży, aby sprawdzić, czy łożysko przodujące utrzymuje się.⁶⁶ Częstotliwość badań kontrolnych zależy od wyjściowego rozpoznania i przebiegu klinicznego:⁶⁷

Jeśli łożysko przodujące zostanie zdiagnozowane podczas rutynowego badania, pacjentka będzie prawdopodobnie miała częstsze badania ultrasonograficzne w celu monitorowania wszelkich zmian w łożysku
Czas przeprowadzenia badania ma kluczowe znaczenie dla postawienia prawidłowej diagnozy
Częstość utrzymywania się łożyska przodującego jest bezpośrednio związana z wiekiem ciążowym w momencie diagnozy ultrasonograficznej⁶⁸

Badanie przesiewowe wszystkich pacjentek i właściwe określenie lokalizacji łożyska, przy użyciu przezpochwowej ultrasonografii po 16 tygodniu ciąży, ma kluczowe znaczenie dla uniknięcia niepotrzebnego niepokoju rodziców przez przedwczesne zdiagnozowanie łożyska przodującego we wczesnej ciąży.⁶⁹

Heterogeniczność w danych epidemiologicznych

Meta-analiza wykazała znaczącą (p<0,001) heterogeniczność między szacunkami badań dotyczącymi częstości występowania łożyska przodującego, częstości występowania łożyska przodującego z PAS i częstości występowania PAS w kohorcie łożyska przodującego.⁷⁰⁷¹

Wysoka heterogeniczność w jakościowych i diagnostycznych danych między badaniami podkreśla potrzebę wdrożenia znormalizowanych protokołów diagnostycznych zarówno dla łożyska przodującego, jak i PAS, w tym określania typu łożyska przodującego i stopnia inwazyjności kosmków.⁷²⁷³⁷⁴

Istnieje potrzeba dalszych prospektywnych, wieloośrodkowych badań z metodologiami partycypacyjnymi, angażującymi lokalnych świadczeniodawców i zarządzających placówkami, aby dokładnie ocenić konsekwencje wysokich wskaźników cięć cesarskich dla zdrowia matki w określonej populacji.⁷⁵⁷⁶

Komplikacje i nadzór w przypadku krwawienia

Najczęstszym objawem łożyska przodującego jest stosunkowo bezbolesne krwawienie z pochwy, które występuje w nawet 90% utrzymujących się przypadków.⁷⁷ Krwawienie przedporodowe (antepartum hemorrhage, APH) jest ważną przyczyną śmiertelności okołoporodowej i zachorowalności matczynej u kobiet w ciąży z łożyskiem przodującym na całym świecie.⁷⁸

Metaanaliza wykazała, że łączna ogólna częstość występowania APH wśród kobiet w ciąży z łożyskiem przodującym wynosiła 51,6% (95% CI 42,7-60,6).⁷⁹ W badaniach prospektywnych częstość występowania APH wynosiła 20,7%, 48,3%, 52,1% i 55,6% odpowiednio w Austrii, we Włoszech, w Arabii Saudyjskiej i w Japonii.⁸⁰

W przypadku większości pierwszych epizodów krwawienia przed 36 tygodniem ciąży zaleca się hospitalizację, ograniczenie aktywności i powstrzymanie się od aktywności seksualnej.⁸¹ Stabilne łożysko przodujące bez krwawienia lub innych powikłań jest optymalnie rozwiązywane w 36-37 6/7 tygodniu ciąży.⁸²

Pacjentki z nisko położonym łożyskiem (łożysko położone ponad 2 cm od ujścia szyjki macicy) mogą kwalifikować się do próby porodu, ale są narażone na zwiększone ryzyko krwotoku poporodowego i pilnego cięcia cesarskiego w porównaniu z kobietami z normalnym położeniem łożyska.⁸³

W krajach o wysokich dochodach wskaźnik umieralności matek związanej z łożyskiem przodującym wynosi mniej niż 1%, ale pozostaje wysoki w krajach o niskich dochodach, gdzie niedokrwistość matki, brak zasobów medycznych i porody domowe są częstsze.⁸⁴

Znaczenie badań naukowych i nadzoru klinicznego

Według ClinicalTrials.gov, przeprowadzono co najmniej 63 badania kliniczne dotyczące łożyska przodującego, w tym 29 zakończonych i 11 trwających.⁸⁵ Te badania przyczyniają się do lepszego zrozumienia epidemiologii, diagnostyki i postępowania w przypadku łożyska przodującego.

Każdy szpital powinien mieć protokół lub algorytm postępowania w przypadku łożyska przodującego.⁸⁶⁸⁷ Postępowanie w przypadku łożyska przodującego jest określane przez wiek ciążowy oraz to, czy pacjentka krwawi, czy jest bezobjawowa.⁸⁸

Poważny charakter łożyska przodującego wymaga starannej oceny, monitorowania i gotowości ze strony położnika. Nieodpowiednie zdiagnozowanie lub leczenie łożyska przodującego może być bardzo niebezpieczne zarówno dla matki, jak i dziecka.⁸⁹

Zaawansowania w nadzorze przedporodowym i wczesnej diagnostyce doprowadziły do znaczącej poprawy wyników związanych z łożyskiem przodującym. Niemniej jednak, łożysko przodujące i łożysko wrośnięte nadal stanowią wyzwania kliniczne z wieloma powiązanymi powikłaniami.⁹⁰

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Materiały źródłowe

#1 Placenta previa: Epidemiology, clinical features, diagnosis, morbidity and mortality – UpToDate
https://www.uptodate.com/contents/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality/print
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os. Sequelae include the need for cesarean birth, and the potential for severe antepartum bleeding, preterm birth, and postpartum hemorrhage. […] This topic will discuss the epidemiology, clinical features, diagnosis, and potential morbidity and mortality of placenta previa. […] In systematic reviews, the pooled prevalence of placenta previa is 4 to 5 per 1000 births but varies worldwide; the reasons for this variation are unclear. The prevalence is much higher at 20 weeks of gestation than at birth because most cases identified early in pregnancy resolve before delivery. In one study, 11 percent of patients undergoing routine transvaginal cervical length screening at or near this gestational age had a previa or placental edge within 2 cm of the internal os.
#2 Placenta previa: Epidemiology, clinical features, diagnosis, morbidity and mortality – UpToDate
https://www.uptodate.com/contents/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os. Sequelae include the need for cesarean birth, and the potential for severe antepartum bleeding, preterm birth, and postpartum hemorrhage. […] In systematic reviews, the pooled prevalence of placenta previa is 4 to 5 per 1000 births but varies worldwide; the reasons for this variation are unclear. The prevalence is much higher at 20 weeks of gestation than at birth because most cases identified early in pregnancy resolve before delivery. In one study, 11 percent of patients undergoing routine transvaginal cervical length screening at or near this gestational age had a previa or placental edge within 2 cm of the internal os. […] This topic will discuss the epidemiology, clinical features, diagnosis, and potential morbidity and mortality of placenta previa.
#3 Placenta previa | Saudi Medical Journal
https://smj.org.sa/content/37/7/762
Objectives: To review cases of placenta previa in the last 13 years in a tertiary teaching hospital to identify risk factors for maternal morbidity. […] The prevalence rate of placenta previa was 4.1 per 1000 births. […] Placenta previa is one of the leading causes of maternal morbidity and mortality. Every hospital must have a protocol, or algorithm for the management of placenta previa. […] The prevalence rate of placenta previa at KAUH was 4.1 per 1000 births. […] In conclusion, placenta previa is one of the major causes of maternal morbidity and mortality. Every hospital must have a protocol or algorithm for the management of placenta previa. Significant risk factors for maternal morbidity include if the placenta is covering the os complete placenta previa, history of previous C/S, emergency.
#4 Volume 2, Chapter 49. Placenta Previa and Accreta
https://www.glowm.com/resources/glowm/cd/pages/v2/v2c049.html
Placenta previa and accreta account for a large percentage of maternal morbidity and mortality in modern obstetrics. […] The current widespread use of ultrasound in obstetrics has greatly advanced our ability to diagnose and manage abnormal obstetric bleeding. […] It is well established that the incidence of placenta previa increases with advancing age and higher parity. […] Most studies report an overall incidence of placenta previa between 1 in 150 to 1 in 300 patients (3 to 6/1000). […] Placenta previa has been reported to result in maternal death in 3/1000 cases, and also has been noted to predispose patients to abruptio placenta. […] These abnormalities of placentation are ominous conditions, contributing significantly to maternal morbidity and mortality and accounting for 1.7% of all maternal deaths in the United States.
#5 Placenta previa: Epidemiology, clinical features, diagnosis, morbidity and mortality – UpToDate
https://www.uptodate.com/contents/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality/print
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os. Sequelae include the need for cesarean birth, and the potential for severe antepartum bleeding, preterm birth, and postpartum hemorrhage. […] This topic will discuss the epidemiology, clinical features, diagnosis, and potential morbidity and mortality of placenta previa. […] In systematic reviews, the pooled prevalence of placenta previa is 4 to 5 per 1000 births but varies worldwide; the reasons for this variation are unclear. The prevalence is much higher at 20 weeks of gestation than at birth because most cases identified early in pregnancy resolve before delivery. In one study, 11 percent of patients undergoing routine transvaginal cervical length screening at or near this gestational age had a previa or placental edge within 2 cm of the internal os.
#6 Placenta previa epidemiology, clinical features, diagnosis, morbidity and mortality up-todate | PDF
https://www.slideshare.net/slideshow/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality-uptodate/102550124
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os. Sequelae include the potential for severe bleeding and preterm birth, as well as the need for cesarean delivery. Placenta previa should be suspected in any pregnant woman beyond 20 weeks of gestation who presents with vaginal bleeding. […] In systematic reviews, the pooled prevalence of placenta previa is about 4 per 1000 births, but varies worldwide. The prevalence is several-fold higher around 20 weeks of gestation (as high as 2 percent), but most previas identified early in pregnancy resolve before delivery. […] Major risk factors for placenta previa include previous placenta previa, previous cesarean delivery, multiple gestation, increasing parity, and increasing maternal age. […] The most common symptom of placenta previa is relatively painless vaginal bleeding, which occurs in up to 90 percent of persistent cases.
#7 Placenta Previa – StatPearls – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK539818/
Placenta previa affects 0.3% to 2% of pregnancies in the third trimester and has become more evident secondary to the increasing rates of cesarean sections.[3][4][6] […] Most cases are diagnosed early on in pregnancy via sonography and others may present to the emergency room with painless vaginal bleeding in the second or third trimester of pregnancy. […] Routine sonography in the first and second trimester of pregnancy provides early identification of placenta previa. It is important to realize that the earlier the diagnosis of placenta previa is, the more likely it is to resolve at delivery secondary to placental migration. Nearly 90% of placentas identified as „low lying” will ultimately resolve by the third trimester.[1][9] Follow up sonogram is recommended at 28 to 32 weeks of gestation to look for persistent placenta previa.[6]
#8 Placenta Praevia: Symptoms, Diagnosis, and Treatment | Doctor
https://patient.info/doctor/placenta-praevia
Placenta praevia affects 0.3% to 2% of pregnancies in the third trimester and the incidence is rising with the increasing caesarean section rate. […] UK data suggest the incidence of placenta acreta is 1.7 per 10,000 births but increases to 577 per 10,000 births in women with both a previous caesarean delivery and placenta praevia.
#9 Placenta Previa: Practice Essentials, Pathophysiology, Etiology
https://emedicine.medscape.com/article/262063-overview
Placenta previa is frequently reported to occur in 0.5% of all US pregnancies. A large, US population-based, 1989-1997 study indicated an incidence of 2.8 per 1000 live births. The risks increase 1.5- to 5-fold with a history of cesarean delivery. A meta-analysis showed that the rate of placenta previa increases with increasing numbers of cesarean deliveries, with a rate of 1% after 1 cesarean delivery, 2.8% after 3 cesarean deliveries, and as high as 3.7% after 5 cesarean deliveries. […] Advanced maternal age has also been strongly associated with an increasing incidence of placenta previa. The incidence of placenta previa after age 35 years reported to be 2%. A further increase to 5% is seen after age 40 years, which is a 9-fold increase when compared to females younger than 20 years.
#10 EM@3AM: Placenta Previa – emDocs
https://www.emdocs.net/em3am-placenta-previa/
Placenta overlying the os to any degree is classified as placenta previa. […] Most placenta previas are diagnosed on routine prenatal transabdominal ultrasonography. […] Incidence: 1 in 200 pregnancies (increasing due to more C-sections being performed). […] Many previas diagnosed in mid-pregnancy will resolve by time of birth due to placental âmigrationâ away from cervix as pregnancy progresses. […] Risk factors: C-section, recurrent abortions, prior uterine surgery, multiparity, older maternal age, smoking, cocaine use, prior previa, multiple gestations. […] Adverse outcomes for both mother and fetus. […] Poor maternal outcomes: increased need for blood transfusions, hysterectomy, ICU admission, sepsis, DIC, postpartum hemorrhage, mortality. […] Poor fetal-neonatal outcomes: increased risk of prematurity, lower birth weight, lower Apgar score, mortality (increased 3- to 4-fold).
#11 Placenta Previa and Birth Injury
https://www.abclawcenters.com/practice-areas/prenatal-birth-injuries/labor-and-delivery-complications-and-errors/placenta-previa/
Placenta previa is estimated to occur in approximately one in every 200 pregnancies in the third trimester of pregnancy. […] The exact cause of placenta previa is unknown, although risk factors have been identified. […] Placenta previa is diagnosed via ultrasound. It can be found during a routine prenatal ultrasound or during an ultrasound administered after vaginal bleeding occurs. Most cases of placenta previa are diagnosed during routine ultrasounds at 16-20 weeks. […] The serious nature of placenta previa requires careful evaluation, monitoring, and preparedness by an obstetrician. Failure to properly diagnose or treat placenta previa can be very dangerous for both mother and baby.
#12 Placenta previa | Radiology Reference Article | Radiopaedia.org
https://radiopaedia.org/articles/placenta-praevia?embed_domain=external.radpair.com%252527%25255B0%25255D%252527%25255B0%25255D&lang=us
Placenta previa has an incidence of 1 in 200 pregnancies ref. […] Placenta previa is associated with several risk factors, including previous placenta previa, previous cesarean section, increased maternal age, increased parity, large placentas, maternal history of smoking, assisted conception, previous manual removal of placenta. […] Placenta previa is a potentially life-threatening condition for both mother and infant. As such, antenatal diagnosis is essential to prepare for childbirth adequately.
#13 Placenta previa | Saudi Medical Journal
https://smj.org.sa/content/37/7/762
Objectives: To review cases of placenta previa in the last 13 years in a tertiary teaching hospital to identify risk factors for maternal morbidity. […] The prevalence rate of placenta previa was 4.1 per 1000 births. […] Placenta previa is one of the leading causes of maternal morbidity and mortality. Every hospital must have a protocol, or algorithm for the management of placenta previa. […] The prevalence rate of placenta previa at KAUH was 4.1 per 1000 births. […] In conclusion, placenta previa is one of the major causes of maternal morbidity and mortality. Every hospital must have a protocol or algorithm for the management of placenta previa. Significant risk factors for maternal morbidity include if the placenta is covering the os complete placenta previa, history of previous C/S, emergency.
#14 Placenta praevia – Wikipedia
https://en.wikipedia.org/wiki/Placenta_praevia
Placenta praevia occurs approximately one of every 200 births globally. […] It has been suggested that rates of placenta praevia are increasing due to increased rates of Caesarean sections. […] Rates of placenta praevia in sub-Saharan Africa are the lowest in the world, averaging 2.7 per 1000 pregnancies. […] In North Africa placenta praevia rates occur in 6.4 per 1000 pregnancies. […] Mainland China has the highest prevalence of placenta praevia in the world, measuring at an average of 12.2 per 1000 pregnancies. […] In the Middle East, placenta praevia rates are lower in both Saudi Arabia (7.3 per 1000) and Israel (4.2 per 1000). […] The continent with the second highest rates for placenta praevia is Australia, where it affects about 9.5 out of every 1000 pregnant women. […] Placenta praevia in Europe occurs in about 3.6 per 1000 pregnancies. […] In Latin America, placenta praevia occurs in about 5.1 per 1000 pregnancies. […] In North America placenta praevia occurs in 2.9 per 1000 pregnancies. […] Research suggests that the incidence of placenta praevia in the U.S. is increasing as a result of the increased rate of Caesarean sections.
#15 Placenta Previa and Placenta Abruption | Article | GLOWM
https://www.glowm.com/article/heading/vol-10–common-obstetric-conditions–placenta-previa-and-placenta-abruption/id/413763
Placenta previa is the implantation of placental tissue partially or entirely within the lower segment of the uterus after 20 weeks of gestation. […] The overall prevalence of placenta previa is estimated as 5.2 per 1000 pregnancies, with marked regional variation. The prevalence is highest among Asian studies (12.2 per 1000 pregnancies) and lower in European (3.6 per 1000 pregnancies), North American (2.9 per 1000 pregnancies) and Sub-Saharan African (2.7 per 1000 pregnancies) studies. […] The risks of placenta previa increases 1.55-fold following cesarean delivery and with increasing numbers of cesarean deliveries, at 1% after one cesarean delivery, 2.8% after three cesarean deliveries, and 3.7% after five cesarean deliveries. […] Placenta previa following prior cesarean sections has been associated with high and increasing risk of placenta accreta syndromes.
#16 Placenta Previa | Radiology Key
https://radiologykey.com/placenta-previa/
Placenta previa is present in approximately 5 in 1000 pregnancies at the time of delivery, with a higher prevalence noted at midgestation. […] Placenta previa is estimated to occur in approximately 5:1000 pregnancies. Worldwide, the incidence has been found to vary, with a higher incidence noted in Asian studies (12.2:1000 pregnancies) and lower incidences in European, North American, and African studies (2.7:1000-3.6:1000 pregnancies). […] One of the primary risk factors for placenta previa is prior cesarean delivery, and the risk increases with increasing numbers of cesarean deliveries. […] Additional risk factors include a history of placenta previa in a prior pregnancy, advanced maternal age, multiparity, multiple pregnancy, smoking, cocaine use, and previous uterine surgery (i.e., curettage, abortion).
#17
https://journals.lww.com/md-journal/fulltext/2016/10040/prevalence_of_placenta_previa_among_deliveries_in.74.aspx
Placenta previa is characterized by the abnormal placenta overlying the endocervical os, and it is known as one of the most feared adverse maternal and fetal-neonatal complications in obstetrics. […] We aimed to obtain overall and regional estimates of placenta previa prevalence among deliveries in Mainland China. […] A total of 80 articles and 86 datasets (including 1,298,548 subjects and 14,199 placenta previa cases) from 1965 through 2015 were included. The pooled overall prevalence of placenta previa among deliveries was 1.24% (95% confidence interval [CI], 1.121.36) in Mainland China during 1965 to 2015. […] The occurrence rate of placenta previa in the region groups Northeast, North, Northwest, Central China, East, South, and Southwest was 1.20%, 1.01%, 1.10%, 1.15%, 0.93%, 1.42%, and 2.01%, respectively.
#18
https://journals.lww.com/md-journal/fulltext/2016/10040/prevalence_of_placenta_previa_among_deliveries_in.74.aspx
The results showed that placenta previa is currently a high-burden disease in Mainland China. […] The trend in the prevalence of placenta previa was steady. […] The prevalence of placenta previa in China (2.01%) was first reported by Guo et al in 1965 with 220 cases in 10,919 pregnancies. […] The prevalence reports varied considerably, ranging from 0.24% in Beijing to 5% in Hainan. […] The overall prevalence of placenta previa was 1.24% (95% CI, 1.121.36), and the forest plot for the overall estimates was shown in Supplementary Fig. 1. […] The prevalence of placenta previa of Northeast, North, Northwest, Central China, East, South, and Southwest were 1.20% (95% CI, 0.651.75), 1.01% (95% CI, 0.711.30), 1.10% (95% CI, 0.801.40), 1.15% (95% CI, 0.901.40), 0.93% (95% CI, 0.781.07), 1.42% (95% CI, 1.161.68), and 2.01% (95% CI, 1.162.86), respectively. […] The geographic distributions of placenta previa were unequal in Mainland China.
#19 Placenta praevia – Wikipedia
https://en.wikipedia.org/wiki/Placenta_praevia
Placenta praevia occurs approximately one of every 200 births globally. […] It has been suggested that rates of placenta praevia are increasing due to increased rates of Caesarean sections. […] Rates of placenta praevia in sub-Saharan Africa are the lowest in the world, averaging 2.7 per 1000 pregnancies. […] In North Africa placenta praevia rates occur in 6.4 per 1000 pregnancies. […] Mainland China has the highest prevalence of placenta praevia in the world, measuring at an average of 12.2 per 1000 pregnancies. […] In the Middle East, placenta praevia rates are lower in both Saudi Arabia (7.3 per 1000) and Israel (4.2 per 1000). […] The continent with the second highest rates for placenta praevia is Australia, where it affects about 9.5 out of every 1000 pregnant women. […] Placenta praevia in Europe occurs in about 3.6 per 1000 pregnancies. […] In Latin America, placenta praevia occurs in about 5.1 per 1000 pregnancies. […] In North America placenta praevia occurs in 2.9 per 1000 pregnancies. […] Research suggests that the incidence of placenta praevia in the U.S. is increasing as a result of the increased rate of Caesarean sections.
#20 Placenta Previa — Taming the SRU
https://www.tamingthesru.com/blog/annals-of-b-pod/b-pod-case/placenta-previa
Placenta previa is defined as a placenta that is in close proximity to, or overlies the internal os of the cervix. It is present to some degree in 1 in 200 pregnancies. […] Risk factors for placenta previa include prior cesarean delivery (with increasing risk with greater number of cesareans), advanced maternal age, recurrent abortions, multiparity, and infertility treatment. […] Notably, rates of placenta previa and accreta have been increasing since the 1950s. This is largely attributable to the increase in cesarean section over this time period. […] Diagnosis of placenta previa is typically via transvaginal ultrasound, which is highly sensitive and specific for the diagnosis. […] Once identified in the ED, consultation with an obstetrician is warranted as these patients often require admission for monitoring at the very least.
#21 Prevalence of placenta previa among deliveries: An update systematic review and meta-analysis after the introduction of the two-child policy in Mainland China â JOGH
https://jogh.org/2024/jogh-14-04108/
The prevalence of placenta previa among Chinese pregnant women was 1.44% (95% confidence interval (CI) = 1.32, 1.56). […] After the implementation of the two-child policy, the prevalence increased significantly, from 1.25% (95% CI = 1.16, 1.34) to 4.12% (95% CI = 3.33, 4.91). […] The prevalence of placenta previa increased significantly from the one-child policy period to the two-child policy period among mainland Chinese pregnant women, with varying trends across regions. This change requires the attention of health officials and timely adjustment of resource allocation policies. […] The overall pooled prevalence of placenta previa was 1.44% (95% confidence interval (CI) = 1.32, 1.56). The prevalence of placenta previa increased significantly after the implementation of the two-child policy, from 1.25% (95% CI = 1.16, 1.34) in the prior period to 4.12% (95% CI = 3.33, 4.91) after the implementation.
#22 Placenta previa: Epidemiology, clinical features, diagnosis, morbidity and mortality – UpToDate
https://www.uptodate.com/contents/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality/print
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os. Sequelae include the need for cesarean birth, and the potential for severe antepartum bleeding, preterm birth, and postpartum hemorrhage. […] This topic will discuss the epidemiology, clinical features, diagnosis, and potential morbidity and mortality of placenta previa. […] In systematic reviews, the pooled prevalence of placenta previa is 4 to 5 per 1000 births but varies worldwide; the reasons for this variation are unclear. The prevalence is much higher at 20 weeks of gestation than at birth because most cases identified early in pregnancy resolve before delivery. In one study, 11 percent of patients undergoing routine transvaginal cervical length screening at or near this gestational age had a previa or placental edge within 2 cm of the internal os.
#23 Placenta previa: Epidemiology, clinical features, diagnosis, morbidity and mortality – UpToDate
https://www.uptodate.com/contents/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os. Sequelae include the need for cesarean birth, and the potential for severe antepartum bleeding, preterm birth, and postpartum hemorrhage. […] In systematic reviews, the pooled prevalence of placenta previa is 4 to 5 per 1000 births but varies worldwide; the reasons for this variation are unclear. The prevalence is much higher at 20 weeks of gestation than at birth because most cases identified early in pregnancy resolve before delivery. In one study, 11 percent of patients undergoing routine transvaginal cervical length screening at or near this gestational age had a previa or placental edge within 2 cm of the internal os. […] This topic will discuss the epidemiology, clinical features, diagnosis, and potential morbidity and mortality of placenta previa.
#24 Placenta Previa – StatPearls – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK539818/
Placenta previa affects 0.3% to 2% of pregnancies in the third trimester and has become more evident secondary to the increasing rates of cesarean sections.[3][4][6] […] Most cases are diagnosed early on in pregnancy via sonography and others may present to the emergency room with painless vaginal bleeding in the second or third trimester of pregnancy. […] Routine sonography in the first and second trimester of pregnancy provides early identification of placenta previa. It is important to realize that the earlier the diagnosis of placenta previa is, the more likely it is to resolve at delivery secondary to placental migration. Nearly 90% of placentas identified as „low lying” will ultimately resolve by the third trimester.[1][9] Follow up sonogram is recommended at 28 to 32 weeks of gestation to look for persistent placenta previa.[6]
#25 EM@3AM: Placenta Previa – emDocs
https://www.emdocs.net/em3am-placenta-previa/
Placenta overlying the os to any degree is classified as placenta previa. […] Most placenta previas are diagnosed on routine prenatal transabdominal ultrasonography. […] Incidence: 1 in 200 pregnancies (increasing due to more C-sections being performed). […] Many previas diagnosed in mid-pregnancy will resolve by time of birth due to placental âmigrationâ away from cervix as pregnancy progresses. […] Risk factors: C-section, recurrent abortions, prior uterine surgery, multiparity, older maternal age, smoking, cocaine use, prior previa, multiple gestations. […] Adverse outcomes for both mother and fetus. […] Poor maternal outcomes: increased need for blood transfusions, hysterectomy, ICU admission, sepsis, DIC, postpartum hemorrhage, mortality. […] Poor fetal-neonatal outcomes: increased risk of prematurity, lower birth weight, lower Apgar score, mortality (increased 3- to 4-fold).
#26 Placenta previa: Practical approach to sonographic evaluation and management
https://www.contemporaryobgyn.net/view/placenta-previa-practical-approach-sonographic-evaluation-and-management
It has been determined to persist in 12% of those diagnosed at 15-19 weeks; 34% at 20-23 weeks; 39% at 24-27 weeks; 62% at 28-31 weeks and 73% at 32-35 weeks. […] Management of a placenta previa is dictated by gestational age and by whether the patient is bleeding or asymptomatic. […] Screening all patients and properly determining placental location, using transvaginal sonography beyond 16 weeks gestation, is critical to avoid causing undue parental anxiety by prematurely diagnosing a placenta previa in early gestation. […] Ob/gyns should be aware of placental migration and normalization of a placenta previa with advancing gestation.
#27 Placenta previa epidemiology, clinical features, diagnosis, morbidity and mortality up-todate | PDF
https://www.slideshare.net/slideshow/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality-uptodate/102550124
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os. Sequelae include the potential for severe bleeding and preterm birth, as well as the need for cesarean delivery. Placenta previa should be suspected in any pregnant woman beyond 20 weeks of gestation who presents with vaginal bleeding. […] In systematic reviews, the pooled prevalence of placenta previa is about 4 per 1000 births, but varies worldwide. The prevalence is several-fold higher around 20 weeks of gestation (as high as 2 percent), but most previas identified early in pregnancy resolve before delivery. […] Major risk factors for placenta previa include previous placenta previa, previous cesarean delivery, multiple gestation, increasing parity, and increasing maternal age. […] The most common symptom of placenta previa is relatively painless vaginal bleeding, which occurs in up to 90 percent of persistent cases.
#28 Placenta previa: Practical approach to sonographic evaluation and management
https://www.contemporaryobgyn.net/view/placenta-previa-practical-approach-sonographic-evaluation-and-management
The majority resolve with advancing gestation with a 0.5% incidence reported at term. However, prevalence of placenta previa is on the rise and there are several risk factors for abnormal placentation, at the forefront of which is prior uterine instrumentation, whether it be cesarean delivery, dilatation and curettage or myomectomy. […] The risk is two-fold higher in case of pre-labor cesarean section in comparison to an intrapartum cesarean section. […] In addition, there are other predisposing factors to placenta previa such as higher-order gestation, advanced maternal age, grand multiparity and pregnancies resulting from assisted reproductive technology. […] The aim of this review is to provide practical tips on diagnosis and management of a placenta previa. […] Timing of the examination is key to arriving at the correct diagnosis. The rate of persistence of a placenta previa is directly related to the gestational age at sonographic diagnosis.
#29 Volume 2, Chapter 49. Placenta Previa and Accreta
https://www.glowm.com/resources/glowm/cd/pages/v2/v2c049.html
The association of both placenta previa and placenta accreta with extensive maternal hemorrhage and transfusion is well documented. […] As preterm intervention and delivery is often required in cases of placenta previa or placenta accreta, these conditions become significant contributors to perinatal morbidity and mortality as well, accounting for as many as 24% of perinatal deaths. […] Placenta accreta occurs most commonly, followed in decreasing frequency by placenta increta and placenta percreta. […] Confirmation of placenta accreta requires histopathologic methods, and so it is possible that incidence is underreported when the condition is focal or not associated with performance of a hysterectomy. […] The most important risk factors for placenta previa and accreta are age, parity, and a history of uterine surgery.
#30 Placenta Previa: Practice Essentials, Pathophysiology, Etiology
https://emedicine.medscape.com/article/262063-overview
Placenta previa is frequently reported to occur in 0.5% of all US pregnancies. A large, US population-based, 1989-1997 study indicated an incidence of 2.8 per 1000 live births. The risks increase 1.5- to 5-fold with a history of cesarean delivery. A meta-analysis showed that the rate of placenta previa increases with increasing numbers of cesarean deliveries, with a rate of 1% after 1 cesarean delivery, 2.8% after 3 cesarean deliveries, and as high as 3.7% after 5 cesarean deliveries. […] Advanced maternal age has also been strongly associated with an increasing incidence of placenta previa. The incidence of placenta previa after age 35 years reported to be 2%. A further increase to 5% is seen after age 40 years, which is a 9-fold increase when compared to females younger than 20 years.
#31 Placenta Previa: Practice Essentials, Pathophysiology, Etiology
https://emedicine.medscape.com/article/262063-overview
Placenta previa is frequently reported to occur in 0.5% of all US pregnancies. A large, US population-based, 1989-1997 study indicated an incidence of 2.8 per 1000 live births. The risks increase 1.5- to 5-fold with a history of cesarean delivery. A meta-analysis showed that the rate of placenta previa increases with increasing numbers of cesarean deliveries, with a rate of 1% after 1 cesarean delivery, 2.8% after 3 cesarean deliveries, and as high as 3.7% after 5 cesarean deliveries. […] Advanced maternal age has also been strongly associated with an increasing incidence of placenta previa. The incidence of placenta previa after age 35 years reported to be 2%. A further increase to 5% is seen after age 40 years, which is a 9-fold increase when compared to females younger than 20 years.
#32 Placenta Previa and Placenta Abruption | Article | GLOWM
https://www.glowm.com/article/heading/vol-10–common-obstetric-conditions–placenta-previa-and-placenta-abruption/id/413763
Placenta previa is the implantation of placental tissue partially or entirely within the lower segment of the uterus after 20 weeks of gestation. […] The overall prevalence of placenta previa is estimated as 5.2 per 1000 pregnancies, with marked regional variation. The prevalence is highest among Asian studies (12.2 per 1000 pregnancies) and lower in European (3.6 per 1000 pregnancies), North American (2.9 per 1000 pregnancies) and Sub-Saharan African (2.7 per 1000 pregnancies) studies. […] The risks of placenta previa increases 1.55-fold following cesarean delivery and with increasing numbers of cesarean deliveries, at 1% after one cesarean delivery, 2.8% after three cesarean deliveries, and 3.7% after five cesarean deliveries. […] Placenta previa following prior cesarean sections has been associated with high and increasing risk of placenta accreta syndromes.
#33 Placenta Previa: Practice Essentials, Pathophysiology, Etiology
https://emedicine.medscape.com/article/262063-overview
Placenta previa is frequently reported to occur in 0.5% of all US pregnancies. A large, US population-based, 1989-1997 study indicated an incidence of 2.8 per 1000 live births. The risks increase 1.5- to 5-fold with a history of cesarean delivery. A meta-analysis showed that the rate of placenta previa increases with increasing numbers of cesarean deliveries, with a rate of 1% after 1 cesarean delivery, 2.8% after 3 cesarean deliveries, and as high as 3.7% after 5 cesarean deliveries. […] Advanced maternal age has also been strongly associated with an increasing incidence of placenta previa. The incidence of placenta previa after age 35 years reported to be 2%. A further increase to 5% is seen after age 40 years, which is a 9-fold increase when compared to females younger than 20 years.
#34 Determinants of Placenta Previa among Pregnant Women Delivered in Public Hospitals South Ethiopia: Unmatched Case-Control Study | medRxiv
https://www.medrxiv.org/content/10.1101/2025.02.02.25321556v1.full
Increased maternal age (35 years), short inter-pregnancy interval of less than 24 months, history of abortions, prior cesarean sections, and having leiomyoma were identified determinants of placenta previa. […] The odds of developing placenta previa was 4.45 among pregnant women with the age of 35 years and above compared to the maternal age less than 35 years [AOR=4.45 (95% C.I =1.2,, 4.99)]. […] The odds of developing placenta previa was 1.89 among the pregnant women with the pregnancy of short inter-pregnancy interval of less than 24 months compared to the women of inter-pregnancy interval of 24 months and above [AOR=1.89 (95% C.I=(1.08, 3.53)]. […] The odds of developing placenta previa was 5.49 among mothers with previous abortions when compared to the women with no prior abortions [AOR=5.49 (955 C.I =2.93, 10.3)].
#35
https://www.ijrcog.org/index.php/ijrcog/article/view/3628
The obstetrical haemorrhage constitutes the first cause of mother death, among the causes of these haemorrhages: the placenta previa. That is why we initiated this study for determine epidemiology of placenta previa in our service. The aim objective of this study was to determine the evolution and epidemiology of the placenta previa in our department. […] We recorded 504 cases of placenta previa among 30323 deliveries (1.7%). […] The most significant rick factors associated with placenta previa are high maternal age, high parity and previous placenta previa, caesarean section and abortion.
#36 Risk of placenta previa in second birth after first birth cesarean section: a population-based study and meta-analysis | BMC Pregnancy and Childbirth | Full Text
https://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/1471-2393-11-95
Evidence about the risk of placenta previa following a previous CS in UK women is limited to results published 25 years ago. […] The overall rate of placenta previa for the cohort at first birth was 3.6 and at second birth was 5.3 per 1000 births. […] The rate of placenta previa at second birth was 4.4 per 1000 births for women with vaginal delivery at first birth and 8.7 for women with CS at first birth (unadjusted odds ratio = 1.88). […] Among women in England, cesarean section in the first delivery increased the risk of placenta previa in the subsequent delivery by 60%. […] Our study has demonstrated that, in addition to women with previous CS, women with advanced maternal age, women with birth intervals of less than one year and women who had a previous placenta previa are at a higher risk of developing placenta previa. Nonetheless, our study suggests that the absolute risk remains small.
#37 Placenta previa epidemiology, clinical features, diagnosis, morbidity and mortality up-todate | PDF
https://www.slideshare.net/slideshow/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality-uptodate/102550124
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os. Sequelae include the potential for severe bleeding and preterm birth, as well as the need for cesarean delivery. Placenta previa should be suspected in any pregnant woman beyond 20 weeks of gestation who presents with vaginal bleeding. […] In systematic reviews, the pooled prevalence of placenta previa is about 4 per 1000 births, but varies worldwide. The prevalence is several-fold higher around 20 weeks of gestation (as high as 2 percent), but most previas identified early in pregnancy resolve before delivery. […] Major risk factors for placenta previa include previous placenta previa, previous cesarean delivery, multiple gestation, increasing parity, and increasing maternal age. […] The most common symptom of placenta previa is relatively painless vaginal bleeding, which occurs in up to 90 percent of persistent cases.
#38
https://www.ijrcog.org/index.php/ijrcog/article/view/3628
The obstetrical haemorrhage constitutes the first cause of mother death, among the causes of these haemorrhages: the placenta previa. That is why we initiated this study for determine epidemiology of placenta previa in our service. The aim objective of this study was to determine the evolution and epidemiology of the placenta previa in our department. […] We recorded 504 cases of placenta previa among 30323 deliveries (1.7%). […] The most significant rick factors associated with placenta previa are high maternal age, high parity and previous placenta previa, caesarean section and abortion.
#39 Placenta previa after prior abortion: a meta-analysis | Biomedical Research and Therapy
http://bmrat.org/index.php/BMRAT/article/view/197
There is controversy regarding the role of prior abortion on placenta previa in subsequent pregnancies. […] The literature search included 872 articles up until January 2017 with 2,134,529 participants. […] Based on OR estimates obtained from case-control and cohort studies, we found a significant association between prior spontaneous abortions and placenta previa (1.77; 95% CI: 1.60, 1.94) and between prior induced abortions and placenta previa (1.36; 95% CI: 1.02, 1.69). […] The meta-analysis study herein showed that prior abortion is a risk factor for placenta previa. […] The meta-analysis described herein and based on observational studies show that there is an association between prior abortion and placenta previa. Our results suggest that prior abortion is a risk factor for placenta previa.
#40 Determinants of Placenta Previa among Pregnant Women Delivered in Public Hospitals South Ethiopia: Unmatched Case-Control Study | medRxiv
https://www.medrxiv.org/content/10.1101/2025.02.02.25321556v1.full
Increased maternal age (35 years), short inter-pregnancy interval of less than 24 months, history of abortions, prior cesarean sections, and having leiomyoma were identified determinants of placenta previa. […] The odds of developing placenta previa was 4.45 among pregnant women with the age of 35 years and above compared to the maternal age less than 35 years [AOR=4.45 (95% C.I =1.2,, 4.99)]. […] The odds of developing placenta previa was 1.89 among the pregnant women with the pregnancy of short inter-pregnancy interval of less than 24 months compared to the women of inter-pregnancy interval of 24 months and above [AOR=1.89 (95% C.I=(1.08, 3.53)]. […] The odds of developing placenta previa was 5.49 among mothers with previous abortions when compared to the women with no prior abortions [AOR=5.49 (955 C.I =2.93, 10.3)].
#41 Determinants of Placenta Previa among Pregnant Women Delivered in Public Hospitals South Ethiopia: Unmatched Case-Control Study | medRxiv
https://www.medrxiv.org/content/10.1101/2025.02.02.25321556v1.full
Increased maternal age (35 years), short inter-pregnancy interval of less than 24 months, history of abortions, prior cesarean sections, and having leiomyoma were identified determinants of placenta previa. […] The odds of developing placenta previa was 4.45 among pregnant women with the age of 35 years and above compared to the maternal age less than 35 years [AOR=4.45 (95% C.I =1.2,, 4.99)]. […] The odds of developing placenta previa was 1.89 among the pregnant women with the pregnancy of short inter-pregnancy interval of less than 24 months compared to the women of inter-pregnancy interval of 24 months and above [AOR=1.89 (95% C.I=(1.08, 3.53)]. […] The odds of developing placenta previa was 5.49 among mothers with previous abortions when compared to the women with no prior abortions [AOR=5.49 (955 C.I =2.93, 10.3)].
#42 Determinants of Placenta Previa among Pregnant Women Delivered in Public Hospitals South Ethiopia: Unmatched Case-Control Study | medRxiv
https://www.medrxiv.org/content/10.1101/2025.02.02.25321556v1.full
Increased maternal age (35 years), short inter-pregnancy interval of less than 24 months, history of abortions, prior cesarean sections, and having leiomyoma were identified determinants of placenta previa. […] The odds of developing placenta previa was 4.45 among pregnant women with the age of 35 years and above compared to the maternal age less than 35 years [AOR=4.45 (95% C.I =1.2,, 4.99)]. […] The odds of developing placenta previa was 1.89 among the pregnant women with the pregnancy of short inter-pregnancy interval of less than 24 months compared to the women of inter-pregnancy interval of 24 months and above [AOR=1.89 (95% C.I=(1.08, 3.53)]. […] The odds of developing placenta previa was 5.49 among mothers with previous abortions when compared to the women with no prior abortions [AOR=5.49 (955 C.I =2.93, 10.3)].
#43 Determinants of Placenta Previa among Pregnant Women Delivered in Public Hospitals South Ethiopia: Unmatched Case-Control Study | medRxiv
https://www.medrxiv.org/content/10.1101/2025.02.02.25321556v1.full
The odds of developing placenta previa was 3.73 among mothers with previous cesarean sections when compared to mothers without prior C/S [AOR=3.73 (95% C.I =1.68, 8.3)]. […] The odds of developing placenta previa was 6.33 among women with women having uterine leiomyoma (fibroids) when compared to women without uterine leiomyoma (fibroids) [AOR=6.33 (95% C.I=2.48, 16.17)].
#44 Volume 2, Chapter 49. Placenta Previa and Accreta
https://www.glowm.com/resources/glowm/cd/pages/v2/v2c049.html
The presence of placenta previa is a well-recognized risk factor for placenta accreta. […] A more recent long-term epidemiologic study found that for all races there was a five-fold increase in the occurrence of placenta previa for women more than 35 years compared to those less than 20 years of age. […] One of the most dramatic risk factors for placenta previa or accreta is clearly the presence of previous cesarean section. […] Although mothers with one previous cesarean had a 2.5-fold increase in the risk of previa, this number multiplied dramatically with increasing number of cesarean sections, peaking at mothers with four or more uterine incisions, who experienced a 38-fold increase in the incidence of placenta previa. […] Smoking has been convincingly linked as a significant risk factor for placenta previa, with a dose-dependent increase of risk.
#45
https://step2.medbullets.com/obstetrics/120369/placenta-previa
Epidemiology […] Incidence […] occurs in approximately 1 per 250 births […] […] Risk factors […] previous placenta previa […] […] previous cesarean delivery […] […] multiple gestations
#46 Placenta previa epidemiology, clinical features, diagnosis, morbidity and mortality up-todate | PDF
https://www.slideshare.net/slideshow/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality-uptodate/102550124
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os. Sequelae include the potential for severe bleeding and preterm birth, as well as the need for cesarean delivery. Placenta previa should be suspected in any pregnant woman beyond 20 weeks of gestation who presents with vaginal bleeding. […] In systematic reviews, the pooled prevalence of placenta previa is about 4 per 1000 births, but varies worldwide. The prevalence is several-fold higher around 20 weeks of gestation (as high as 2 percent), but most previas identified early in pregnancy resolve before delivery. […] Major risk factors for placenta previa include previous placenta previa, previous cesarean delivery, multiple gestation, increasing parity, and increasing maternal age. […] The most common symptom of placenta previa is relatively painless vaginal bleeding, which occurs in up to 90 percent of persistent cases.
#47 Placenta previa: Practical approach to sonographic evaluation and management
https://www.contemporaryobgyn.net/view/placenta-previa-practical-approach-sonographic-evaluation-and-management
The majority resolve with advancing gestation with a 0.5% incidence reported at term. However, prevalence of placenta previa is on the rise and there are several risk factors for abnormal placentation, at the forefront of which is prior uterine instrumentation, whether it be cesarean delivery, dilatation and curettage or myomectomy. […] The risk is two-fold higher in case of pre-labor cesarean section in comparison to an intrapartum cesarean section. […] In addition, there are other predisposing factors to placenta previa such as higher-order gestation, advanced maternal age, grand multiparity and pregnancies resulting from assisted reproductive technology. […] The aim of this review is to provide practical tips on diagnosis and management of a placenta previa. […] Timing of the examination is key to arriving at the correct diagnosis. The rate of persistence of a placenta previa is directly related to the gestational age at sonographic diagnosis.
#48 Placenta previa | Radiology Reference Article | Radiopaedia.org
https://radiopaedia.org/articles/placenta-praevia?embed_domain=external.radpair.com%252527%25255B0%25255D%252527%25255B0%25255D&lang=us
Placenta previa has an incidence of 1 in 200 pregnancies ref. […] Placenta previa is associated with several risk factors, including previous placenta previa, previous cesarean section, increased maternal age, increased parity, large placentas, maternal history of smoking, assisted conception, previous manual removal of placenta. […] Placenta previa is a potentially life-threatening condition for both mother and infant. As such, antenatal diagnosis is essential to prepare for childbirth adequately.
#49 Epidemiology of placenta previa accreta: a systematic review and meta-analysis
https://pmc.ncbi.nlm.nih.gov/articles/PMC6858111/
To estimate the prevalence and incidence of placenta previa complicated by placenta accreta spectrum (PAS) and to examine the different criteria being used for the diagnosis. […] The meta-analysis indicated a significant (p0.001) heterogeneity between study estimates for the prevalence of placenta previa, the prevalence of placenta previa with PAS and the incidence of PAS in the placenta previa cohort. […] The median prevalence of placenta previa was 0.56% (IQR 0.391.24) whereas the median prevalence of placenta previa with PAS was 0.07% (IQR 0.050.16). The incidence of PAS in women with a placenta previa was 11.10% (IQR 7.6517.35). […] The high heterogeneity in qualitative and diagnostic data between studies emphasises the need to implement standardised protocols for the diagnoses of both placenta previa and PAS, including the type of placenta previa and grade of villous invasiveness.
#50 Epidemiology of placenta previa accreta: a systematic review and meta-analysis | BMJ Open
https://bmjopen.bmj.com/content/9/11/e031193
The meta-analysis indicated a significant (p0.001) heterogeneity between study estimates for the prevalence of placenta previa, the prevalence of placenta previa with PAS and the incidence of PAS in the placenta previa cohort. […] The median prevalence of placenta previa was 0.56% (IQR 0.391.24) whereas the median prevalence of placenta previa with PAS was 0.07% (IQR 0.050.16). The incidence of PAS in women with a placenta previa was 11.10% (IQR 7.6517.35). […] The prevalence of PAS in the general population of women giving birth varies widely. […] A systematic review and meta-analysis of the prevalence of placenta praevia has found evidence suggestive of regional variation. […] There is a need for further prospective multicentre studies with participatory methodologies involving local service providers and facility management to accurately evaluate the consequences of high caesarean sections rates on maternal health within a particular population.
#51
https://discovery.ucl.ac.uk/id/eprint/10086240/
Epidemiology of placenta previa accreta: a systematic review and meta-analysis. […] Objective To estimate the prevalence and incidence of placenta previa complicated by placenta accreta spectrum (PAS) and to examine the different criteria being used for the diagnosis. […] The primary outcomes were overall prevalence of placenta previa, incidence of PAS according to the type of placenta previa and the reported clinical outcomes, including the number of peripartum hysterectomies and direct maternal mortality. […] The meta-analysis indicated a significant (p0.001) heterogeneity between study estimates for the prevalence of placenta previa, the prevalence of placenta previa with PAS and the incidence of PAS in the placenta previa cohort. […] The median prevalence of placenta previa was 0.56% (IQR 0.39-1.24) whereas the median prevalence of placenta previa with PAS was 0.07% (IQR 0.05-0.16).
#52
https://discovery.ucl.ac.uk/id/eprint/10086240/
The incidence of PAS in women with a placenta previa was 11.10% (IQR 7.65-17.35). […] The high heterogeneity in qualitative and diagnostic data between studies emphasises the need to implement standardised protocols for the diagnoses of both placenta previa and PAS, including the type of placenta previa and grade of villous invasiveness.
#53 EM@3AM: Placenta Previa – emDocs
https://www.emdocs.net/em3am-placenta-previa/
Placenta accreta (placental attachment to myometrium) occurs in approximately 10% of patients with placenta previa. […] Stable placenta previa without bleeding or other complications is optimally delivered at 36 â 37 6/7 weeks of gestation. […] Painless vaginal bleeding after 18 weeks gestation is placenta previa until proven otherwise. […] Classic presentation is painless 2nd or 3rd trimester vaginal bleeding. […] Diagnosed by transvaginal ultrasound (95% sensitivity, 93% specificity).
#54 Epidemiology of placenta previa accreta: a systematic review and meta-analysis | BMJ Open
https://bmjopen.bmj.com/content/9/11/e031193
The high heterogeneity in qualitative and diagnostic data between studies emphasises the need to implement standardised protocols for the diagnoses of both placenta previa and PAS, including the type of placenta previa and grade of villous invasiveness. […] Over the last two decades, a growing body of epidemiology research has identified the effect of the rapid increase in caesarean delivery rates on the risks of PAS.610 The main additional risk factor after a previous caesarean delivery is placenta previa. […] A large multicentric US cohort study noted that for women presenting with placenta previa and prior caesarean delivery, the risk of PAS was 3%, 11%, 40%, 61% and 67% for first, second, third, fourth and fifth or more caesarean deliveries, respectively. […] A national casecontrol study using the UK Obstetric Surveillance System found that the incidence of PAS increases from 1.7 per 10000 births overall to 577 per 10000 births in women with both a previous caesarean delivery and placenta previa.
#55 Epidemiology of placenta previa accreta: a systematic review and meta-analysis | BMJ Open
https://bmjopen.bmj.com/content/9/11/e031193
The high heterogeneity in qualitative and diagnostic data between studies emphasises the need to implement standardised protocols for the diagnoses of both placenta previa and PAS, including the type of placenta previa and grade of villous invasiveness. […] Over the last two decades, a growing body of epidemiology research has identified the effect of the rapid increase in caesarean delivery rates on the risks of PAS.610 The main additional risk factor after a previous caesarean delivery is placenta previa. […] A large multicentric US cohort study noted that for women presenting with placenta previa and prior caesarean delivery, the risk of PAS was 3%, 11%, 40%, 61% and 67% for first, second, third, fourth and fifth or more caesarean deliveries, respectively. […] A national casecontrol study using the UK Obstetric Surveillance System found that the incidence of PAS increases from 1.7 per 10000 births overall to 577 per 10000 births in women with both a previous caesarean delivery and placenta previa.
#56 Placenta Praevia: Symptoms, Diagnosis, and Treatment | Doctor
https://patient.info/doctor/placenta-praevia
Placenta praevia affects 0.3% to 2% of pregnancies in the third trimester and the incidence is rising with the increasing caesarean section rate. […] UK data suggest the incidence of placenta acreta is 1.7 per 10,000 births but increases to 577 per 10,000 births in women with both a previous caesarean delivery and placenta praevia.
#57 Placenta previa: Practical approach to sonographic evaluation and management
https://www.contemporaryobgyn.net/view/placenta-previa-practical-approach-sonographic-evaluation-and-management
Identifying abnormal placentation is crucial for determining the correct management of at-risk pregnancies and minimizing morbidity and mortality of both mother and child. […] Assessment of placental location in the mid-trimester fetal anatomic scan is a critical component of sonographic examination as recommended by various national and international guidelines. It allows for timely identification of at-risk pregnancies to ensure close surveillance for optimal peripartum management that minimizes maternal and neonatal morbidity and mortality. […] Due to varying criteria used at different gestational ages, the true incidence of placenta previa is difficult to determine, and at 18 to 23 weeks it has been reported to be around 5% when evaluated by transabdominal scan and 1.5% when evaluated by transvaginal scan.
#58 Placenta previa – Diagnosis & treatment – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/placenta-previa/diagnosis-treatment/drc-20352773
Placenta previa is diagnosed through ultrasound, either during a routine prenatal appointment or after an episode of vaginal bleeding. Most cases of placenta previa are diagnosed during a second-trimester ultrasound exam. […] If placenta previa is diagnosed during a routine exam, you’ll likely have more-frequent ultrasound exams to monitor any changes in the placenta. […] Placenta previa is usually diagnosed during a routine ultrasound exam or after an episode of vaginal bleeding.
#59 Placenta previa – Diagnosis & treatment – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/placenta-previa/diagnosis-treatment/drc-20352773
Placenta previa is diagnosed through ultrasound, either during a routine prenatal appointment or after an episode of vaginal bleeding. Most cases of placenta previa are diagnosed during a second-trimester ultrasound exam. […] If placenta previa is diagnosed during a routine exam, you’ll likely have more-frequent ultrasound exams to monitor any changes in the placenta. […] Placenta previa is usually diagnosed during a routine ultrasound exam or after an episode of vaginal bleeding.
#60 Placenta Previa and Placenta Abruption | Article | GLOWM
https://www.glowm.com/article/heading/vol-10–common-obstetric-conditions–placenta-previa-and-placenta-abruption/id/413763
The diagnosis of placenta previa is based on history, clinical examination findings and supporting imaging studies. Increasingly, however, routine ultrasonography has resulted in earlier diagnosis of asymptomatic cases without or prior to clinical presentation. […] The clinical presentation of painless and often recurrent vaginal bleeding after 20 weeks of pregnancy is often diagnostic of placenta previa unless proven otherwise. In such women placenta previa can only be excluded after imaging studies. […] The imaging studies for placental location can be obstetric ultrasonography (transabdominal, transvaginal or transperineal) and magnetic resonance imaging. Ultrasonography is the initial imaging study for confirmation or ruling out placenta previa. Transabdominal sonography is confirmatory of placenta previa in 96% of cases.
#61 Placenta Previa and Placenta Abruption | Article | GLOWM
https://www.glowm.com/article/heading/vol-10–common-obstetric-conditions–placenta-previa-and-placenta-abruption/id/413763
The diagnosis of placenta previa is based on history, clinical examination findings and supporting imaging studies. Increasingly, however, routine ultrasonography has resulted in earlier diagnosis of asymptomatic cases without or prior to clinical presentation. […] The clinical presentation of painless and often recurrent vaginal bleeding after 20 weeks of pregnancy is often diagnostic of placenta previa unless proven otherwise. In such women placenta previa can only be excluded after imaging studies. […] The imaging studies for placental location can be obstetric ultrasonography (transabdominal, transvaginal or transperineal) and magnetic resonance imaging. Ultrasonography is the initial imaging study for confirmation or ruling out placenta previa. Transabdominal sonography is confirmatory of placenta previa in 96% of cases.
#62 EM@3AM: Placenta Previa – emDocs
https://www.emdocs.net/em3am-placenta-previa/
Placenta accreta (placental attachment to myometrium) occurs in approximately 10% of patients with placenta previa. […] Stable placenta previa without bleeding or other complications is optimally delivered at 36 â 37 6/7 weeks of gestation. […] Painless vaginal bleeding after 18 weeks gestation is placenta previa until proven otherwise. […] Classic presentation is painless 2nd or 3rd trimester vaginal bleeding. […] Diagnosed by transvaginal ultrasound (95% sensitivity, 93% specificity).
#63 Placenta previa epidemiology, clinical features, diagnosis, morbidity and mortality up-todate | PDF
https://www.slideshare.net/slideshow/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality-uptodate/102550124
The diagnosis of placenta previa is based on sonography and requires the identification of echogenic homogeneous placental tissue over the internal cervical os. […] Maternal morbidity from placenta previa is primarily related to antepartum and/or postpartum hemorrhage. […] In resource-rich countries, the maternal mortality rate associated with placenta previa is less than 1 percent, but remains high in resource-poor countries where maternal anemia, lack of medical resources, and home births are more common. […] The principal causes of neonatal morbidity and mortality are related to preterm delivery. In large studies, approximately 15 percent of patients with placenta previa delivered before 34 weeks of gestation.
#64 Placenta previa: Practical approach to sonographic evaluation and management
https://www.contemporaryobgyn.net/view/placenta-previa-practical-approach-sonographic-evaluation-and-management
Identifying abnormal placentation is crucial for determining the correct management of at-risk pregnancies and minimizing morbidity and mortality of both mother and child. […] Assessment of placental location in the mid-trimester fetal anatomic scan is a critical component of sonographic examination as recommended by various national and international guidelines. It allows for timely identification of at-risk pregnancies to ensure close surveillance for optimal peripartum management that minimizes maternal and neonatal morbidity and mortality. […] Due to varying criteria used at different gestational ages, the true incidence of placenta previa is difficult to determine, and at 18 to 23 weeks it has been reported to be around 5% when evaluated by transabdominal scan and 1.5% when evaluated by transvaginal scan.
#65 Placenta Previa – StatPearls – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK539818/
Placenta previa affects 0.3% to 2% of pregnancies in the third trimester and has become more evident secondary to the increasing rates of cesarean sections.[3][4][6] […] Most cases are diagnosed early on in pregnancy via sonography and others may present to the emergency room with painless vaginal bleeding in the second or third trimester of pregnancy. […] Routine sonography in the first and second trimester of pregnancy provides early identification of placenta previa. It is important to realize that the earlier the diagnosis of placenta previa is, the more likely it is to resolve at delivery secondary to placental migration. Nearly 90% of placentas identified as „low lying” will ultimately resolve by the third trimester.[1][9] Follow up sonogram is recommended at 28 to 32 weeks of gestation to look for persistent placenta previa.[6]
#66 Placenta Previa – StatPearls – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK539818/
Placenta previa affects 0.3% to 2% of pregnancies in the third trimester and has become more evident secondary to the increasing rates of cesarean sections.[3][4][6] […] Most cases are diagnosed early on in pregnancy via sonography and others may present to the emergency room with painless vaginal bleeding in the second or third trimester of pregnancy. […] Routine sonography in the first and second trimester of pregnancy provides early identification of placenta previa. It is important to realize that the earlier the diagnosis of placenta previa is, the more likely it is to resolve at delivery secondary to placental migration. Nearly 90% of placentas identified as „low lying” will ultimately resolve by the third trimester.[1][9] Follow up sonogram is recommended at 28 to 32 weeks of gestation to look for persistent placenta previa.[6]
#67 Placenta previa – Diagnosis & treatment – Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/placenta-previa/diagnosis-treatment/drc-20352773
Placenta previa is diagnosed through ultrasound, either during a routine prenatal appointment or after an episode of vaginal bleeding. Most cases of placenta previa are diagnosed during a second-trimester ultrasound exam. […] If placenta previa is diagnosed during a routine exam, you’ll likely have more-frequent ultrasound exams to monitor any changes in the placenta. […] Placenta previa is usually diagnosed during a routine ultrasound exam or after an episode of vaginal bleeding.
#68 Placenta previa: Practical approach to sonographic evaluation and management
https://www.contemporaryobgyn.net/view/placenta-previa-practical-approach-sonographic-evaluation-and-management
It has been determined to persist in 12% of those diagnosed at 15-19 weeks; 34% at 20-23 weeks; 39% at 24-27 weeks; 62% at 28-31 weeks and 73% at 32-35 weeks. […] Management of a placenta previa is dictated by gestational age and by whether the patient is bleeding or asymptomatic. […] Screening all patients and properly determining placental location, using transvaginal sonography beyond 16 weeks gestation, is critical to avoid causing undue parental anxiety by prematurely diagnosing a placenta previa in early gestation. […] Ob/gyns should be aware of placental migration and normalization of a placenta previa with advancing gestation.
#69 Placenta previa: Practical approach to sonographic evaluation and management
https://www.contemporaryobgyn.net/view/placenta-previa-practical-approach-sonographic-evaluation-and-management
It has been determined to persist in 12% of those diagnosed at 15-19 weeks; 34% at 20-23 weeks; 39% at 24-27 weeks; 62% at 28-31 weeks and 73% at 32-35 weeks. […] Management of a placenta previa is dictated by gestational age and by whether the patient is bleeding or asymptomatic. […] Screening all patients and properly determining placental location, using transvaginal sonography beyond 16 weeks gestation, is critical to avoid causing undue parental anxiety by prematurely diagnosing a placenta previa in early gestation. […] Ob/gyns should be aware of placental migration and normalization of a placenta previa with advancing gestation.
#70 Epidemiology of placenta previa accreta: a systematic review and meta-analysis | BMJ Open
https://bmjopen.bmj.com/content/9/11/e031193
The meta-analysis indicated a significant (p0.001) heterogeneity between study estimates for the prevalence of placenta previa, the prevalence of placenta previa with PAS and the incidence of PAS in the placenta previa cohort. […] The median prevalence of placenta previa was 0.56% (IQR 0.391.24) whereas the median prevalence of placenta previa with PAS was 0.07% (IQR 0.050.16). The incidence of PAS in women with a placenta previa was 11.10% (IQR 7.6517.35). […] The prevalence of PAS in the general population of women giving birth varies widely. […] A systematic review and meta-analysis of the prevalence of placenta praevia has found evidence suggestive of regional variation. […] There is a need for further prospective multicentre studies with participatory methodologies involving local service providers and facility management to accurately evaluate the consequences of high caesarean sections rates on maternal health within a particular population.
#71 Epidemiology of placenta previa accreta: a systematic review and meta-analysis
https://pmc.ncbi.nlm.nih.gov/articles/PMC6858111/
To estimate the prevalence and incidence of placenta previa complicated by placenta accreta spectrum (PAS) and to examine the different criteria being used for the diagnosis. […] The meta-analysis indicated a significant (p0.001) heterogeneity between study estimates for the prevalence of placenta previa, the prevalence of placenta previa with PAS and the incidence of PAS in the placenta previa cohort. […] The median prevalence of placenta previa was 0.56% (IQR 0.391.24) whereas the median prevalence of placenta previa with PAS was 0.07% (IQR 0.050.16). The incidence of PAS in women with a placenta previa was 11.10% (IQR 7.6517.35). […] The high heterogeneity in qualitative and diagnostic data between studies emphasises the need to implement standardised protocols for the diagnoses of both placenta previa and PAS, including the type of placenta previa and grade of villous invasiveness.
#72 Epidemiology of placenta previa accreta: a systematic review and meta-analysis | BMJ Open
https://bmjopen.bmj.com/content/9/11/e031193
The high heterogeneity in qualitative and diagnostic data between studies emphasises the need to implement standardised protocols for the diagnoses of both placenta previa and PAS, including the type of placenta previa and grade of villous invasiveness. […] Over the last two decades, a growing body of epidemiology research has identified the effect of the rapid increase in caesarean delivery rates on the risks of PAS.610 The main additional risk factor after a previous caesarean delivery is placenta previa. […] A large multicentric US cohort study noted that for women presenting with placenta previa and prior caesarean delivery, the risk of PAS was 3%, 11%, 40%, 61% and 67% for first, second, third, fourth and fifth or more caesarean deliveries, respectively. […] A national casecontrol study using the UK Obstetric Surveillance System found that the incidence of PAS increases from 1.7 per 10000 births overall to 577 per 10000 births in women with both a previous caesarean delivery and placenta previa.
#73 Epidemiology of placenta previa accreta: a systematic review and meta-analysis
https://pmc.ncbi.nlm.nih.gov/articles/PMC6858111/
To estimate the prevalence and incidence of placenta previa complicated by placenta accreta spectrum (PAS) and to examine the different criteria being used for the diagnosis. […] The meta-analysis indicated a significant (p0.001) heterogeneity between study estimates for the prevalence of placenta previa, the prevalence of placenta previa with PAS and the incidence of PAS in the placenta previa cohort. […] The median prevalence of placenta previa was 0.56% (IQR 0.391.24) whereas the median prevalence of placenta previa with PAS was 0.07% (IQR 0.050.16). The incidence of PAS in women with a placenta previa was 11.10% (IQR 7.6517.35). […] The high heterogeneity in qualitative and diagnostic data between studies emphasises the need to implement standardised protocols for the diagnoses of both placenta previa and PAS, including the type of placenta previa and grade of villous invasiveness.
#74 Epidemiology of placenta previa accreta: a systematic review and meta-analysis
https://pmc.ncbi.nlm.nih.gov/articles/PMC6858111/
This study provides the first comprehensive evaluation of the epidemiology of placenta previa complicated by placenta accreta spectrum (PAS). […] The prevalence of PAS in the general population of women giving birth varies widely. […] There is a need for further prospective multicentre studies with participatory methodologies involving local service providers and facility management to accurately evaluate the consequences of high caesarean sections rates on maternal health within a particular population. […] Our study supports implementation, in both clinical practice and in reporting data on placenta previa accreta in the medical literature, of standardised protocols for prenatal diagnosis of both placenta previa and PAS, for the clinical diagnosis of PAS at birth and for the histopathological confirmation examination.
#75 Epidemiology of placenta previa accreta: a systematic review and meta-analysis | BMJ Open
https://bmjopen.bmj.com/content/9/11/e031193
The meta-analysis indicated a significant (p0.001) heterogeneity between study estimates for the prevalence of placenta previa, the prevalence of placenta previa with PAS and the incidence of PAS in the placenta previa cohort. […] The median prevalence of placenta previa was 0.56% (IQR 0.391.24) whereas the median prevalence of placenta previa with PAS was 0.07% (IQR 0.050.16). The incidence of PAS in women with a placenta previa was 11.10% (IQR 7.6517.35). […] The prevalence of PAS in the general population of women giving birth varies widely. […] A systematic review and meta-analysis of the prevalence of placenta praevia has found evidence suggestive of regional variation. […] There is a need for further prospective multicentre studies with participatory methodologies involving local service providers and facility management to accurately evaluate the consequences of high caesarean sections rates on maternal health within a particular population.
#76 Epidemiology of placenta previa accreta: a systematic review and meta-analysis
https://pmc.ncbi.nlm.nih.gov/articles/PMC6858111/
This study provides the first comprehensive evaluation of the epidemiology of placenta previa complicated by placenta accreta spectrum (PAS). […] The prevalence of PAS in the general population of women giving birth varies widely. […] There is a need for further prospective multicentre studies with participatory methodologies involving local service providers and facility management to accurately evaluate the consequences of high caesarean sections rates on maternal health within a particular population. […] Our study supports implementation, in both clinical practice and in reporting data on placenta previa accreta in the medical literature, of standardised protocols for prenatal diagnosis of both placenta previa and PAS, for the clinical diagnosis of PAS at birth and for the histopathological confirmation examination.
#77 Placenta previa epidemiology, clinical features, diagnosis, morbidity and mortality up-todate | PDF
https://www.slideshare.net/slideshow/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality-uptodate/102550124
Placenta previa refers to the presence of placental tissue that extends over the internal cervical os. Sequelae include the potential for severe bleeding and preterm birth, as well as the need for cesarean delivery. Placenta previa should be suspected in any pregnant woman beyond 20 weeks of gestation who presents with vaginal bleeding. […] In systematic reviews, the pooled prevalence of placenta previa is about 4 per 1000 births, but varies worldwide. The prevalence is several-fold higher around 20 weeks of gestation (as high as 2 percent), but most previas identified early in pregnancy resolve before delivery. […] Major risk factors for placenta previa include previous placenta previa, previous cesarean delivery, multiple gestation, increasing parity, and increasing maternal age. […] The most common symptom of placenta previa is relatively painless vaginal bleeding, which occurs in up to 90 percent of persistent cases.
#78 Prevalence of antepartum hemorrhage in women with placenta previa: a systematic review and meta-analysis | Scientific Reports
https://www.nature.com/articles/srep40320
Antepartum hemorrhage (APH) is an important cause of perinatal mortality and maternal morbidity in pregnant women with placenta previa in the world. […] The pooled overall prevalence of APH among pregnant women with placenta previa was 51.6% (95% CI 42.760.6) in a heterogeneous set of studies (I2=97.9). […] In conclusion, the prevalence of APH was a high condition among pregnant women with placenta previa. […] Studies have suggested that pregnant women with placenta previa experience higher rates of APH than the general women. […] The prevalence may vary due to the maternal age, previa location (anterior vs. posterior), previa types (complete vs. incomplete), the nature of the population studied, lifestyle habits, the use of different diagnosis criteria, and other potential characteristics.
#79 Prevalence of antepartum hemorrhage in women with placenta previa: a systematic review and meta-analysis | Scientific Reports
https://www.nature.com/articles/srep40320
Antepartum hemorrhage (APH) is an important cause of perinatal mortality and maternal morbidity in pregnant women with placenta previa in the world. […] The pooled overall prevalence of APH among pregnant women with placenta previa was 51.6% (95% CI 42.760.6) in a heterogeneous set of studies (I2=97.9). […] In conclusion, the prevalence of APH was a high condition among pregnant women with placenta previa. […] Studies have suggested that pregnant women with placenta previa experience higher rates of APH than the general women. […] The prevalence may vary due to the maternal age, previa location (anterior vs. posterior), previa types (complete vs. incomplete), the nature of the population studied, lifestyle habits, the use of different diagnosis criteria, and other potential characteristics.
#80 Prevalence of antepartum hemorrhage in women with placenta previa: a systematic review and meta-analysis | Scientific Reports
https://www.nature.com/articles/srep40320
A reliable estimate of APH in placenta previa is important for informing efforts to prevent, treat, and identify causes of APH among pregnant women with placenta previa and would contribute to the planning and implantation of relevant public health strategies. […] The pooled estimated of the prevalence showed that more than half (51.6%) of pregnant women experience APH. […] Given the high heterogeneity, it was best to consider the confidence interval rather than the pooled result. […] The prevalence of APH reported in studies was considerably different among different countries in pregnant women with placenta previa. […] In prospective studies, the prevalence of APH was 20.7%, 48.3%, 52.1%, and 55.6% in Austria, Italy, Saudi Arabia, and Japan, respectively. […] When assessed by geographic region, the prevalence was high in Asia (53.4%), intermediate in North America (53.2%) and Europe (48.5%), and low in Africa (33.8%) in this meta-analysis.
#81 Placenta Previa – Gynecology and Obstetrics – Merck Manual Professional Edition
https://www.merckmanuals.com/professional/gynecology-and-obstetrics/antenatal-complications/placenta-previa
Incidence of placenta previa is approximately 5/1000 deliveries (1). […] Consider placenta previa in all women who have vaginal bleeding during the second or third trimester. […] For most first bleeding episodes before 36 weeks, recommend hospitalization, modified activity, and abstinence from sexual activity. […] Cesarean delivery is indicated when the mother or fetus is unstable or, if mother and fetus are stable, at 36 to 37 6/7 weeks.
#82 EM@3AM: Placenta Previa – emDocs
https://www.emdocs.net/em3am-placenta-previa/
Placenta accreta (placental attachment to myometrium) occurs in approximately 10% of patients with placenta previa. […] Stable placenta previa without bleeding or other complications is optimally delivered at 36 â 37 6/7 weeks of gestation. […] Painless vaginal bleeding after 18 weeks gestation is placenta previa until proven otherwise. […] Classic presentation is painless 2nd or 3rd trimester vaginal bleeding. […] Diagnosed by transvaginal ultrasound (95% sensitivity, 93% specificity).
#83 Placenta Previa – StatPearls – NCBI Bookshelf
https://www.ncbi.nlm.nih.gov/books/NBK539818/
Patients with a low-lying placenta, placenta lies greater than 2cm from the cervical os, may qualify for a trial of labor but are at an increased risk for postpartum hemorrhage and emergent cesarean section compared to women with normal placentation.[6][21] There is no consensus for the recommended mode of delivery for marginal placenta previa.[6]
#84 Placenta previa epidemiology, clinical features, diagnosis, morbidity and mortality up-todate | PDF
https://www.slideshare.net/slideshow/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality-uptodate/102550124
The diagnosis of placenta previa is based on sonography and requires the identification of echogenic homogeneous placental tissue over the internal cervical os. […] Maternal morbidity from placenta previa is primarily related to antepartum and/or postpartum hemorrhage. […] In resource-rich countries, the maternal mortality rate associated with placenta previa is less than 1 percent, but remains high in resource-poor countries where maternal anemia, lack of medical resources, and home births are more common. […] The principal causes of neonatal morbidity and mortality are related to preterm delivery. In large studies, approximately 15 percent of patients with placenta previa delivered before 34 weeks of gestation.
#85 Top Published Expert Doctors for Placenta Previa
https://findexpertmd.com/d/Placenta_Previa
393 top medical experts on Placenta Previa across 65 countries and 25 U.S. states, including 232 MDs (Physicians). This is based on an objective analysis of their Scientific Publications, Clinical Trials, Medicare, and NIH Grants. […] Clinical Trials ClinicalTrials.gov: at least 63 including 29 Completed, 11 Recruiting.
#86 Placenta previa | Saudi Medical Journal
https://smj.org.sa/content/37/7/762
Objectives: To review cases of placenta previa in the last 13 years in a tertiary teaching hospital to identify risk factors for maternal morbidity. […] The prevalence rate of placenta previa was 4.1 per 1000 births. […] Placenta previa is one of the leading causes of maternal morbidity and mortality. Every hospital must have a protocol, or algorithm for the management of placenta previa. […] The prevalence rate of placenta previa at KAUH was 4.1 per 1000 births. […] In conclusion, placenta previa is one of the major causes of maternal morbidity and mortality. Every hospital must have a protocol or algorithm for the management of placenta previa. Significant risk factors for maternal morbidity include if the placenta is covering the os complete placenta previa, history of previous C/S, emergency.
#87 Incidence, risk factors, and maternal outcomes of major degree placenta previa | Saudi Medical Journal
https://smj.org.sa/content/44/9/912
Placenta previa is a significant cause of maternal morbidity and mortality in Saudi Arabia, they concluded. Every hospital must have a defined protocol and a dedicated team to manage all PP cases. […] The well known risk factors for PP/PAS were typically present among our patients, including elder age, grand multiparity parity, and repeated cesarean deliveries. […] The risk of PP/PAS is verified to proportionally increase with the number of past C-sections in a previous systematic review. […] The need for our PP patients for transfusion with blood products directly reflects the hemorrhagic morbidity; up to 87.3% (n=261) of them received packed RBCs, while 113 (37.8%) patients received fresh frozen plasma. […] Finally, only one maternal death was recorded among our patients, and the calculated maternal mortality rate per major PP/PAS patients is 0.3% (n=1).
#88 Placenta previa: Practical approach to sonographic evaluation and management
https://www.contemporaryobgyn.net/view/placenta-previa-practical-approach-sonographic-evaluation-and-management
It has been determined to persist in 12% of those diagnosed at 15-19 weeks; 34% at 20-23 weeks; 39% at 24-27 weeks; 62% at 28-31 weeks and 73% at 32-35 weeks. […] Management of a placenta previa is dictated by gestational age and by whether the patient is bleeding or asymptomatic. […] Screening all patients and properly determining placental location, using transvaginal sonography beyond 16 weeks gestation, is critical to avoid causing undue parental anxiety by prematurely diagnosing a placenta previa in early gestation. […] Ob/gyns should be aware of placental migration and normalization of a placenta previa with advancing gestation.
#89 Placenta Previa and Birth Injury
https://www.abclawcenters.com/practice-areas/prenatal-birth-injuries/labor-and-delivery-complications-and-errors/placenta-previa/
Placenta previa is estimated to occur in approximately one in every 200 pregnancies in the third trimester of pregnancy. […] The exact cause of placenta previa is unknown, although risk factors have been identified. […] Placenta previa is diagnosed via ultrasound. It can be found during a routine prenatal ultrasound or during an ultrasound administered after vaginal bleeding occurs. Most cases of placenta previa are diagnosed during routine ultrasounds at 16-20 weeks. […] The serious nature of placenta previa requires careful evaluation, monitoring, and preparedness by an obstetrician. Failure to properly diagnose or treat placenta previa can be very dangerous for both mother and baby.
#90 Volume 2, Chapter 49. Placenta Previa and Accreta
https://www.glowm.com/resources/glowm/cd/pages/v2/v2c049.html
Overall, any circumstances that tend to cause uterine damage, myometrial scarring, or deficient development of the decidua may predispose a patient to these placental abnormalities. […] Advances in antenatal surveillance and early diagnosis have led to significant improvements in outcomes associated with placenta previa. […] Nonetheless, placenta previa and placenta accreta continue to present clinical challenges with many associated complications.