Materiały źródłowe

• #1 Placenta Previa: Symptoms, Causes & Treatments

  https://my.clevelandclinic.org/health/diseases/24211-placenta-previa

  Placenta previa occurs in about 1 in 200 pregnancies. Pregnancy care providers usually diagnose it in the second trimester during an ultrasound. […] Pregnancy care providers usually identify placenta previa in a routine ultrasound around 20 weeks of pregnancy. Its sometimes found when a person experiences symptoms of placenta previa like vaginal bleeding. Your provider will recommend ultrasounds to monitor the placement of the placenta for the remainder of your pregnancy. […] Your healthcare provider will diagnose placenta previa using ultrasounds that show the inside of the female reproductive system: […] Both types of ultrasound show the images on a monitor or screen. Your pregnancy care provider will determine how much of your cervix is covered by the placenta and recommend treatment.

• #1 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. […] The initial diagnosis may be done with an ultrasound device on your abdomen. For more accurate images, you may also need a transvaginal ultrasound, which uses a wandlike device placed inside your vagina. Your provider will take care with the position of the device so as not to disrupt the placenta or cause bleeding. […] Placenta previa is usually diagnosed during a routine ultrasound exam or after an episode of vaginal bleeding.

• #1 Placenta previa | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/placenta-praevia?lang=us

  In the case of a complete placenta previa, a cesarian section is required for delivery to avoid the risk of fetal and maternal hemorrhage. […] Transvaginal ultrasound scan is more accurate to assess placenta previa, the transabdominal scan may overdiagnose it in up to one-quarter of cases. […] When diagnosed in the second trimester, a third-trimester ultrasound scan at 32 weeks should be performed to reassess the placenta position.

• #1 Placenta Previa Workup: Approach Considerations, Laboratory Studies, Ultrasonography

  https://emedicine.medscape.com/article/262063-workup

  Transvaginal ultrasonography is considered the gold standard for the diagnosis of placenta previa. This imaging modality is accurate, cost-effective, and well tolerated. […] The distance between the placental edge and internal cervical os on transvaginal ultrasonography after 35 weeks gestation is also valuable in planning the route of delivery. […] Magnetic resonance imaging (MRI) may be used for planning the delivery in that it may help identify placenta accreta (adherence of the placenta to myometrium), placenta increta (invasion through myometrium), or placenta percreta (invasion all the way through the myometrium into serosa, frequently into the bladder).

• #1 Placenta Previa – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK539818/

  Placenta previa is the complete or partial covering of the internal os of the cervix with the placenta. […] 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. […] If there is a concern for placenta previa, then a transvaginal sonogram should be performed to confirm the location of the placenta. […] With the diagnosis of placenta previa, the patient is scheduled for elective delivery at 36 to 37 weeks via cesarean section. […] Patients with excessive or continuous vaginal bleeding should be delivered via cesarean section regardless of gestational age. […] Delivery should be performed from 36 to 37 full weeks, via cesarean section, in uncomplicated cases. […] Patients diagnosed with placenta previa prior to vaginal bleeding should have multiple discussions with the OB/GYN regarding management and expectations.

• #1 Placenta previa | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/placenta-praevia?lang=us

  Placenta previa is an abnormally low-lying placenta covering the internal cervical os. As a common cause of antepartum hemorrhage, placenta previa is a potentially life-threatening condition for both mother and infant. As such, antenatal diagnosis is essential to prepare for childbirth adequately. […] Due to placental trophotropism, the diagnosis of a placenta previa is not made before 16 weeks. […] A low-lying placenta is relatively common in the second-trimester morphology scan, as the fetus grows and the uterus expands, the lower uterine segment thins and grows at a faster rate, such that in most cases the placenta is no longer low-lying by a follow-up transabdominal ultrasound. In asymptomatic women, this is recommended at 32 weeks, and if the placenta is persistently low-lying (including placenta previa), a further follow-up transvaginal ultrasound is recommended at 36 weeks.

• #1 Placenta Previa Workup: Approach Considerations, Laboratory Studies, Ultrasonography

  https://emedicine.medscape.com/article/262063-workup

  In the workup of vaginal bleeding in pregnancy, ultrasonographic visualization of placentation is critical. A digital examination is contraindicated under these circumstances until placental location is determined secondary to the risk of massive hemorrhage. […] Ideally, placental location should be identified during an anatomy scan between 18 and 20 weeks’ gestation. In women with either placenta previa or a low-lying placenta, a repeat ultrasonographic evaluation at 32 weeks is indicated for coordination of mode of delivery. […] The following laboratory tests are indicated in women with suspected placenta previa: Rh compatibility test, levels of fibrin split products (FSP) and fibrinogen, Prothrombin time (PT)/activated partial thromboplastin time (aPTT), Blood type and cross; hold for at least 4 units, Complete blood cell (CBC) count, Amniocentesis and fetal lung maturity testing, if necessary.

• #1 Placenta previa – Symptoms, diagnosis and treatment | BMJ Best Practice US

  https://bestpractice.bmj.com/topics/en-us/667

  Placenta previa (PP) is an uncommon complication of pregnancy. Usually diagnosed on routine ultrasound done for other reasons, but may present with painless vaginal bleeding in the second or third trimester. […] Digital vaginal examination should not be performed on women with active vaginal bleeding until the position of the placenta is known with certainty. […] PP diagnosed in the second trimester is likely to resolve as pregnancy progresses. […] In women with a scarred uterus (most commonly from a prior cesarean section), PP may be associated with placenta accreta spectrum (previously known as abnormally adherent placenta and morbidly adherent placenta), where the placenta attaches to the myometrial layer of the uterus. […] Key diagnostic factors include scarred uterus, presence of other risk factors, painless vaginal bleeding, and absence of cervical/vaginal causes of bleeding on speculum examination. […] 1st tests to order include uterine ultrasound with color flow Doppler analysis, CBC, and type and crossmatch.

• #1 Diagnosis of placenta previa by transvaginal sonography – PubMed

  https://pubmed.ncbi.nlm.nih.gov/8333928/

  The evolution of the sonographic diagnosis of placenta previa is reviewed with special emphasis on transvaginal sonography (TVS), which has been proved accurate at diagnosing different degrees of placenta previa, such as complete, partial, marginal and low-lying. […] In conclusion, TVS should be the principal diagnostic modality used in the work-up of an obstetric patient with vaginal bleeding. The ease of performance and the clarity and accuracy of method and the additional information about implantation that it can provide will soon make TVS the 'golden standard’ in the diagnostic process of placenta previa.

• #1 Placenta Previa and Low Lying Placenta – London Pregnancy Clinic

  https://www.londonpregnancy.com/placenta-previa/

  Placenta previa, also known as a low-lying placenta, is a condition in pregnancy where the placenta attaches lower in the womb than usual, often covering or being close to the cervix (the opening to the birth canal). This placement can cause issues, especially as the cervix starts to thin and open later in pregnancy. […] Placenta previa is usually diagnosed during the routine 20-week anatomy scan, where a detailed ultrasound can reveal the placentas location. The scan allows the sonographer or obstetrician to assess whether the placenta is low-lying and if it partially or fully covers the cervix. […] If placenta previa is detected, additional scans may be scheduled throughout the pregnancy to monitor whether the placenta moves upwards as the uterus expands. […] Regular follow-up scans in the third trimester are essential to monitor any changes and to assess whether a caesarean delivery may be necessary.

• #1 Placenta praevia – Symptoms, diagnosis and treatment | BMJ Best Practice

  https://bestpractice.bmj.com/topics/en-gb/667

  Placenta praevia (PP) is an uncommon complication of pregnancy. Usually diagnosed on routine ultrasound done for other reasons, but may present with painless vaginal bleeding in the second or third trimester. […] Classified as PP if the placenta is directly covering the cervical os, or as low-lying placenta if the placental edge is 2 cm from the cervical os. […] Digital vaginal examination should not be performed on women with active vaginal bleeding until the position of the placenta is known with certainty. […] Caesarean section will generally be necessary in all cases of PP persisting after 36 weeks’ gestation. […] PP diagnosed in the second trimester is likely to resolve as pregnancy progresses. […] In women with a scarred uterus (most commonly from a prior caesarean section), PP may be associated with placenta accreta spectrum (previously known as abnormally adherent placenta and morbidly adherent placenta), where the placenta attaches to the myometrial layer of the uterus.

• #1 Placenta Previa – Gynecology and Obstetrics – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/gynecology-and-obstetrics/antenatal-complications/placenta-previa

  Placenta previa is implantation of the placenta over or near the internal os of the cervix. Diagnosis is by ultrasonography. […] Transvaginal ultrasonography is an accurate, safe way to diagnose placenta previa. […] Consider placenta previa in all women who have vaginal bleeding during the second or third trimester. […] 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.

• #1 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

  Transvaginal sonography (TVS) is safe and superior to the transabdominal ultrasound. […] The diagnosis is typically reserved for pregnancies over 20 weeks of gestation. […] The major clinical findings are vaginal bleeding and abdominal pain, often accompanied by hypertonic uterine contractions, uterine tenderness, and a nonreassuring fetal heart rate (FHR) pattern. […] 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.

• #1 Placenta previa: Practical approach to sonographic evaluation and management

  https://www.contemporaryobgyn.net/view/placenta-previa-practical-approach-sonographic-evaluation-and-management

  Several techniques can be employed to evaluate the placenta, the lower uterine segment, and cord insertion to screen for a placenta previa. […] Timing of the examination is key to arriving at the correct diagnosis. […] 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. […] In case of normalization, it is important to screen for vasa previa. […] In case of persistence, precautionary steps should be taken to safeguard both mother and baby.

• #1 Placenta Previa – Causes, Symptoms, Treatment, Diagnosis – MedBroadcast.com

  https://medbroadcast.com/condition/getcondition/placenta-previa

  In placenta previa, the placenta starts forming very low in the uterus or even over the cervix (the opening of the uterus that leads to the vagina). This obstruction impairs normal vaginal delivery of the baby at birth. […] The condition may be diagnosed by an ultrasound showing the position of the placenta. If it is detected late in the first or early in the second trimester, often the placenta’s location will shift as the uterus enlarges. This can be followed by serial ultrasound. […] If you have been diagnosed with placenta previa, your doctor will avoid digital (which means using the fingers) examination of the vagina and the cervix, as this could cause the placenta to tear and lead to heavy bleeding. […] The treatment for placenta previa is usually aimed at minimizing symptoms and ensuring the pregnancy completes 36 weeks. The goal of this treatment is safe delivery of the fetus as close to term as possible by caesarean section. […] Once placenta previa has been diagnosed, further bleeding and complications may be avoided by ensuring the parent has complete bed rest, sometimes in the hospital.

• #1 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. […] 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. […] Approximately 20% of previas will resolve prior to delivery, through so called placental migration. […] As placenta accreta usually presents in conjunction with placenta previa, the diagnosis is most often made by ultrasonography, either as part of routine antenatal testing or due to vaginal bleeding in the second or third trimester. […] Placenta previa is a potentially life-threatening diagnosis often complicated by accreta.

• #1 Placenta Accreta Spectrum | ACOG

  https://www.acog.org/clinical/clinical-guidance/obstetric-care-consensus/articles/2018/12/placenta-accreta-spectrum

  Antenatal diagnosis of placenta accreta spectrum is highly desirable because outcomes are optimized when delivery occurs at a level III or IV maternal care facility before the onset of labor or bleeding and with avoidance of placental disruption. […] The primary diagnostic modality for antenatal diagnosis is obstetric ultrasonography. […] Although ultrasound evaluation is important, the absence of ultrasound findings does not preclude a diagnosis of placenta accreta spectrum; thus, clinical risk factors remain equally important as predictors of placenta accreta spectrum by ultrasound findings. […] The use of color flow Doppler imaging may facilitate the diagnosis. […] Many studies report very high sensitivity and specificity for obstetric ultrasonography in the diagnosis of placenta accreta spectrum.

• #1 Placenta Previa and Low Lying Placenta – London Pregnancy Clinic

  https://www.londonpregnancy.com/placenta-previa/

  Placenta previa can increase the risk of bleeding during pregnancy and delivery, which is why timely diagnosis and regular follow-up are essential. […] If the placenta continues to cover the cervix towards the end of the pregnancy, a caesarean section will be planned to ensure a safe delivery. […] In most cases, a vaginal delivery is not possible if the placenta is still covering the cervix near the time of delivery. Placenta previa can obstruct the birth canal, making a caesarean section the safest option for both mother and baby. […] Hospitalisation may be recommended if you experience severe bleeding or other complications related to placenta previa.

• #1 Placenta Accreta Spectrum | ACOG

  https://www.acog.org/clinical/clinical-guidance/obstetric-care-consensus/articles/2018/12/placenta-accreta-spectrum

  These reports may overestimate the accuracy of ultrasonography for the diagnosis of placenta accreta spectrum. […] It is advisable, whenever possible, to refer women with clinical risk factors for placenta accreta spectrum to centers with experience and expertise in imaging and diagnosis of the condition. […] Magnetic resonance imaging (MRI) is the other major tool used for the antenatal diagnosis of placenta accreta spectrum. […] The accuracy of MRI for the prediction of placenta accreta spectrum is reasonably good, with a systematic review reporting sensitivities of 75-100% and specificities of 65-100%. […] It is unclear whether MRI improves diagnosis of placenta accreta spectrum beyond that achieved with ultrasonography. […] The optimal timing and number of ultrasound examinations in suspected placenta accreta spectrum are unclear. […] Ideally, women with suspected placenta accreta spectrum diagnosed in the antenatal period based on imaging or clinical acumen should be delivered at a level III or IV center with considerable experience whenever possible to improve outcomes.

• #1 Placenta Previa Causes, Symptoms, and Treatments

  https://www.upmc.com/services/womens-health/conditions/placenta-previa

  Placenta previa occurs when the placenta partially or completely blocks the opening of your cervix. […] The most common way doctors find placenta previa is with a normal ultrasound. Your doctor may perform other types of ultrasounds to confirm placenta previa. […] If the placenta is not covering your cervix, you may still be able to deliver vaginally. […] Depending on how far along you are, the doctor will likely watch and wait to see if the placenta moves on its own. […] The goal of managing placenta previa is for you to carry your pregnancy as far to term as possible.

• #1

  https://link.springer.com/article/10.1007/s44196-023-00237-2

  Objective To analyze the diagnostic value of MRI in placenta previa. […] MRI examination is an important way for clinical diagnosis of placenta previa, and it is worth popularizing. […] The detection rate of central type, marginal type and partial type in group A was higher than that in group B. […] With surgery and pathology as the gold standard, the diagnostic accuracy and sensitivity of group A were higher than that of group B, and the rate of missed diagnosis was lower than that of group B. […] There were differences in the imaging manifestations of the pregnant women, such as the uneven signal in the placenta, the increased/thickened blood vessels in the placenta, and the unclear boundary between the placenta and the uterus. […] MRI technology can provide clearer and more accurate images, especially for soft tissue imaging.

• #1 Placenta previa | March of Dimes

  https://www.marchofdimes.org/find-support/topics/pregnancy/placenta-previa

  Placenta previa is a condition in which the placenta lies very low in the uterus and covers all or part of the opening to the cervical opening that sits at the top of the vagina. […] A prenatal test that uses sound waves to show a picture of your baby in the womb (ultrasound) usually can find placenta previa and determine the placentas location. In some cases, your provider may do an ultrasound through the birth canal (transvaginal ultrasound) or a translabial ultrasound instead. In places where its available, three-dimensional ultrasound may be used. […] Even if you dont have vaginal bleeding, a routine, second trimester ultrasound may show that you have placenta previa. […] Placenta previa found in the second trimester requires repeat follow-up ultrasounds to assure that the cervix is no longer blocked. If the placenta is no longer covering the cervical opening, you can usually have a vaginal delivery.

• #1

  https://link.springer.com/article/10.1007/s44196-023-00237-2

  In the diagnosis of placenta previa, MRI technology can directly observe the location and size of the placenta and cervix, and can clearly reflect the distance between the placenta and the cervix, the coverage area and degree of the placenta, as well as the length and opening degree of the cervix. […] MRI can also detect abnormal placental lesions, such as placental abruption, placental transposition, placental thickening and other lesions, which helps to take effective treatment measures in time to ensure the health of pregnant women and fetuses. […] The detection rate of central type preposition in group A was higher than that in group B, with significant difference in data comparison. […] The reason is that MRI technology can obtain high-resolution images without using radiation, and has high accuracy and sensitivity for the detection of placenta previa.

• #1

  https://link.springer.com/article/10.1007/s44196-023-00237-2

  MRI technology has the advantage of high resolution, which can clearly show the location and size of the placenta and cervix. […] MRI can be imaged on multiple planes, including transverse, sagittal and coronal, and can observe the relationship between placenta and cervix more comprehensively and stereoscopically. […] The MRI manifestations of placental implantation are: uneven signal in the placenta, increased/thickened vascular shadows in the placenta, and unclear boundary between the placenta and uterus. […] The combination of deep learning and medical imaging can be divided into two levels: image and pixel. […] The method based on deep learning can analyze and learn a large number of MRI images, thus improving the diagnostic accuracy and accuracy. […] MRI examination based on deep learning can improve the operation level and film reading technology of imaging personnel, find potential and hidden lesions, and have higher diagnostic accuracy for diseases such as placenta previa.

• #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

  Placenta previa should be suspected in any pregnant person beyond 20 weeks of gestation who presents with vaginal bleeding. […] 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. […] Diagnostic criteria […] Ultrasonography […] Transabdominal ultrasound […] Diagnostic performance […] Technique and pitfalls […] Transvaginal ultrasound […] Diagnostic performance […] TVUS findings predictive of antepartum bleeding. […] Magnetic resonance imaging.

• #1 Placenta Previa – Nomenclature, Diagnosis and Clinical Management – The ObG Project

  https://www.obgproject.com/2017/02/07/placenta-previa-nomenclature-diagnosis-clinical-management/

  Placenta previa: Cesarean delivery only […] Most cases of placenta previa will be identified prenatally by prenatal ultrasound. […] Transvaginal ultrasound is the recommended approach. […] Transvaginal ultrasound is more accurate than transabdominal approach. […] If placenta previa is suspected on transabdominal ultrasound, a transvaginal ultrasound should be performed. […] Placenta previa may be seen in 1 to 4% of second trimester ultrasound exams. […] 10 to 20% of previas diagnosed at 20 weeks gestation will remain a previa in the late 3rd trimester. […] Repeat ultrasound at 32 weeks gestation. […] The incidence of placenta previa is increased by the number of previous cesarean sections, the number of previous spontaneous deliveries, the number of elective terminations, prior uterine surgery, maternal parity, maternal age, smoking, cocaine use, multiple gestations, and prior placenta previa. […] There is an increased risk of postpartum hemorrhage in patients with placenta previa.

• #1 Placenta Praevia and Placenta Accreta: Diagnosis and Management (Green-top Guideline No. 27a) | RCOG

  https://www.rcog.org.uk/guidance/browse-all-guidance/green-top-guidelines/placenta-praevia-and-placenta-accreta-diagnosis-and-management-green-top-guideline-no-27a/

  Placenta praevia and placenta accreta are associated with high maternal and neonatal morbidity and mortality. […] Determining placental location is one of the first aims of routine midpregnancy (18+6 to 21+6 weeks of gestation) transabdominal obstetric ultrasound examination. […] The purpose of this guideline is to describe the diagnostic modalities and review the evidence-based approach to the clinical management of pregnancies complicated by placenta praevia and placenta accreta.

• #1 British Journal Of Midwifery – Placenta praevia: Diagnosis and management

  https://www.britishjournalofmidwifery.com/content/clinical-practice/placenta-praevia-diagnosis-and-management/

  Placenta praevia occurs when the placenta implants in the lower uterine segment. It is often first diagnosed at the 20-week routine anomaly scan and affects approximately 1:200 women. […] The management of this obstetric complication requires a multidisciplinary approach to antenatal diagnosis and monitoring, birth planning and postnatal care to improve maternal and neonatal outcomes. […] Pregnancy complicated by placenta praevia or placenta accreta presents numerous and varied challenges for both the woman and her maternity care team due to the associated levels of maternal and fetal morbidity and significant demand on health resources. […] A continuous increase in the incidence of placenta praevia, including placenta accreta, is anticipated due to rising caesarean rates. […] More recent studies regarding risk factors for placenta praevia support this and additionally link placenta praevia to increased maternal age, multiple gestation, high parity and smoking.

• #2 Placenta Previa – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK539818/

  Placenta previa is the complete or partial covering of the internal os of the cervix with the placenta. […] 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. […] If there is a concern for placenta previa, then a transvaginal sonogram should be performed to confirm the location of the placenta. […] With the diagnosis of placenta previa, the patient is scheduled for elective delivery at 36 to 37 weeks via cesarean section. […] Patients with excessive or continuous vaginal bleeding should be delivered via cesarean section regardless of gestational age. […] Delivery should be performed from 36 to 37 full weeks, via cesarean section, in uncomplicated cases. […] Patients diagnosed with placenta previa prior to vaginal bleeding should have multiple discussions with the OB/GYN regarding management and expectations.

• #2 Placenta Previa > Fact Sheets > Yale Medicine

  https://www.yalemedicine.org/conditions/placenta-previa

  Placenta previa is often diagnosed at the anatomy ultrasound, during the early part pregnancy. […] Doctors typically diagnose placenta previa early in a pregnancy via ultrasound. However, it can also be diagnosed if a woman experiences bleeding during pregnancy. […] Ultrasound is the key diagnostic test used to confirm placenta previa. This helps doctors determine the location of the placenta.

• #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 should be suspected in any pregnant person beyond 20 weeks of gestation who presents with vaginal bleeding. […] 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. […] Diagnostic criteria […] Ultrasonography […] Transabdominal ultrasound […] Diagnostic performance […] Technique and pitfalls […] Transvaginal ultrasound […] Diagnostic performance […] TVUS findings predictive of antepartum bleeding. […] Magnetic resonance imaging.

• #2 Diagnosis of placenta previa by transvaginal sonography – PubMed

  https://pubmed.ncbi.nlm.nih.gov/8333928/

  The evolution of the sonographic diagnosis of placenta previa is reviewed with special emphasis on transvaginal sonography (TVS), which has been proved accurate at diagnosing different degrees of placenta previa, such as complete, partial, marginal and low-lying. […] In conclusion, TVS should be the principal diagnostic modality used in the work-up of an obstetric patient with vaginal bleeding. The ease of performance and the clarity and accuracy of method and the additional information about implantation that it can provide will soon make TVS the 'golden standard’ in the diagnostic process of placenta previa.

• #2 Placenta praevia – Symptoms, diagnosis and treatment | BMJ Best Practice

  https://bestpractice.bmj.com/topics/en-gb/667

  Key diagnostic factors include scarred uterus, presence of other risk factors, painless vaginal bleeding, and absence of cervical/vaginal causes of bleeding on speculum examination. […] 1st investigations to order include uterine ultrasound with colour flow Doppler analysis, FBC, and type and cross-match. […] Investigations to consider include MRI placenta, INR/PTT, fibrinogen, and fibrinogen degradation products, and Kleihauer-Betke test.

• #2 Placenta previa – Symptoms, diagnosis and treatment | BMJ Best Practice US

  https://bestpractice.bmj.com/topics/en-us/667

  Placenta previa (PP) is an uncommon complication of pregnancy. Usually diagnosed on routine ultrasound done for other reasons, but may present with painless vaginal bleeding in the second or third trimester. […] Digital vaginal examination should not be performed on women with active vaginal bleeding until the position of the placenta is known with certainty. […] PP diagnosed in the second trimester is likely to resolve as pregnancy progresses. […] In women with a scarred uterus (most commonly from a prior cesarean section), PP may be associated with placenta accreta spectrum (previously known as abnormally adherent placenta and morbidly adherent placenta), where the placenta attaches to the myometrial layer of the uterus. […] Key diagnostic factors include scarred uterus, presence of other risk factors, painless vaginal bleeding, and absence of cervical/vaginal causes of bleeding on speculum examination. […] 1st tests to order include uterine ultrasound with color flow Doppler analysis, CBC, and type and crossmatch.

• #2 Placenta previa | March of Dimes

  https://www.marchofdimes.org/find-support/topics/pregnancy/placenta-previa

  Placenta previa is a condition in which the placenta lies very low in the uterus and covers all or part of the opening to the cervical opening that sits at the top of the vagina. […] A prenatal test that uses sound waves to show a picture of your baby in the womb (ultrasound) usually can find placenta previa and determine the placentas location. In some cases, your provider may do an ultrasound through the birth canal (transvaginal ultrasound) or a translabial ultrasound instead. In places where its available, three-dimensional ultrasound may be used. […] Even if you dont have vaginal bleeding, a routine, second trimester ultrasound may show that you have placenta previa. […] Placenta previa found in the second trimester requires repeat follow-up ultrasounds to assure that the cervix is no longer blocked. If the placenta is no longer covering the cervical opening, you can usually have a vaginal delivery.

• #2 Placenta praevia – Symptoms, diagnosis and treatment | BMJ Best Practice

  https://bestpractice.bmj.com/topics/en-gb/667

  Placenta praevia (PP) is an uncommon complication of pregnancy. Usually diagnosed on routine ultrasound done for other reasons, but may present with painless vaginal bleeding in the second or third trimester. […] Classified as PP if the placenta is directly covering the cervical os, or as low-lying placenta if the placental edge is 2 cm from the cervical os. […] Digital vaginal examination should not be performed on women with active vaginal bleeding until the position of the placenta is known with certainty. […] Caesarean section will generally be necessary in all cases of PP persisting after 36 weeks’ gestation. […] PP diagnosed in the second trimester is likely to resolve as pregnancy progresses. […] In women with a scarred uterus (most commonly from a prior caesarean section), PP may be associated with placenta accreta spectrum (previously known as abnormally adherent placenta and morbidly adherent placenta), where the placenta attaches to the myometrial layer of the uterus.

• #2 Placenta Previa Treatment| New York & Manhattan | OBGYN

  https://www.alextepperobgyn.com/pregnancy/obstetrical-care/placenta-previa/

  Placenta previa is diagnosed through ultrasound, usually a combination of abdominal ultrasound and transvaginal ultrasound. […] There are two main types of placenta previa, including complete previa and marginal previa. With complete previa, the placenta covers the whole opening of the cervix. With marginal previa, the placenta does not completely cover the opening of the cervix. […] While there is no cure for placenta previa, there are ways to manage the bleeding caused by this condition. Overall, management will depend on how much bleeding you are experiencing, how far along your pregnancy is, your and your baby’s health, and the position of the placenta and baby. […] If you are experiencing the symptoms associated with placenta previa or are in need of placenta previa monitoring and management, contact our office today. Your first step will be to schedule an appointment with Dr. Tepper.

• #2 Placenta previa | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/placenta-praevia?lang=us

  In the case of a complete placenta previa, a cesarian section is required for delivery to avoid the risk of fetal and maternal hemorrhage. […] Transvaginal ultrasound scan is more accurate to assess placenta previa, the transabdominal scan may overdiagnose it in up to one-quarter of cases. […] When diagnosed in the second trimester, a third-trimester ultrasound scan at 32 weeks should be performed to reassess the placenta position.

• #2 Placenta Previa Differential Diagnoses

  https://emedicine.medscape.com/article/262063-differential

  Instruments or fingers should not be placed near the cervix during a vaginal examination, because uncontrolled bleeding can result. Do not perform vaginal or rectal examinations in an outpatient or emergency department setting unless ultrasonography findings have ruled out placenta previa. […] Rarely, ultrasonography is unavailable and a digital examination is necessary. If this is the case, the digital examination should be performed in the operating room under double setup conditions (ie, one team ready for emergent cesarean delivery and one team ready for uneventful vaginal delivery). […] Transvaginal ultrasound: does it help in the diagnosis of placenta previa?. […] Guideline No. 402: Diagnosis and Management of Placenta Previa.

• #2 Placenta Previa – Nomenclature, Diagnosis and Clinical Management – The ObG Project

  https://www.obgproject.com/2017/02/07/placenta-previa-nomenclature-diagnosis-clinical-management/

  Placenta previa: Cesarean delivery only […] Most cases of placenta previa will be identified prenatally by prenatal ultrasound. […] Transvaginal ultrasound is the recommended approach. […] Transvaginal ultrasound is more accurate than transabdominal approach. […] If placenta previa is suspected on transabdominal ultrasound, a transvaginal ultrasound should be performed. […] Placenta previa may be seen in 1 to 4% of second trimester ultrasound exams. […] 10 to 20% of previas diagnosed at 20 weeks gestation will remain a previa in the late 3rd trimester. […] Repeat ultrasound at 32 weeks gestation. […] The incidence of placenta previa is increased by the number of previous cesarean sections, the number of previous spontaneous deliveries, the number of elective terminations, prior uterine surgery, maternal parity, maternal age, smoking, cocaine use, multiple gestations, and prior placenta previa. […] There is an increased risk of postpartum hemorrhage in patients with placenta previa.

• #2 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. […] The aim of this review is to provide practical tips on diagnosis and management of a placenta previa. […] Ultrasound plays a critical role in placental localization whether at the point-of-care setting or during screening examinations.

• #2 Placenta Previa – Gynecology and Obstetrics – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/gynecology-and-obstetrics/antenatal-complications/placenta-previa

  Placenta previa is implantation of the placenta over or near the internal os of the cervix. Diagnosis is by ultrasonography. […] Transvaginal ultrasonography is an accurate, safe way to diagnose placenta previa. […] Consider placenta previa in all women who have vaginal bleeding during the second or third trimester. […] 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.

• #2

  https://link.springer.com/article/10.1007/s44196-023-00237-2

  MRI technology has the advantage of high resolution, which can clearly show the location and size of the placenta and cervix. […] MRI can be imaged on multiple planes, including transverse, sagittal and coronal, and can observe the relationship between placenta and cervix more comprehensively and stereoscopically. […] The MRI manifestations of placental implantation are: uneven signal in the placenta, increased/thickened vascular shadows in the placenta, and unclear boundary between the placenta and uterus. […] The combination of deep learning and medical imaging can be divided into two levels: image and pixel. […] The method based on deep learning can analyze and learn a large number of MRI images, thus improving the diagnostic accuracy and accuracy. […] MRI examination based on deep learning can improve the operation level and film reading technology of imaging personnel, find potential and hidden lesions, and have higher diagnostic accuracy for diseases such as placenta previa.

• #2 Placenta Accreta Spectrum | ACOG

  https://www.acog.org/clinical/clinical-guidance/obstetric-care-consensus/articles/2018/12/placenta-accreta-spectrum

  These reports may overestimate the accuracy of ultrasonography for the diagnosis of placenta accreta spectrum. […] It is advisable, whenever possible, to refer women with clinical risk factors for placenta accreta spectrum to centers with experience and expertise in imaging and diagnosis of the condition. […] Magnetic resonance imaging (MRI) is the other major tool used for the antenatal diagnosis of placenta accreta spectrum. […] The accuracy of MRI for the prediction of placenta accreta spectrum is reasonably good, with a systematic review reporting sensitivities of 75-100% and specificities of 65-100%. […] It is unclear whether MRI improves diagnosis of placenta accreta spectrum beyond that achieved with ultrasonography. […] The optimal timing and number of ultrasound examinations in suspected placenta accreta spectrum are unclear. […] Ideally, women with suspected placenta accreta spectrum diagnosed in the antenatal period based on imaging or clinical acumen should be delivered at a level III or IV center with considerable experience whenever possible to improve outcomes.

• #2

  https://link.springer.com/article/10.1007/s44196-023-00237-2

  Objective To analyze the diagnostic value of MRI in placenta previa. […] MRI examination is an important way for clinical diagnosis of placenta previa, and it is worth popularizing. […] The detection rate of central type, marginal type and partial type in group A was higher than that in group B. […] With surgery and pathology as the gold standard, the diagnostic accuracy and sensitivity of group A were higher than that of group B, and the rate of missed diagnosis was lower than that of group B. […] There were differences in the imaging manifestations of the pregnant women, such as the uneven signal in the placenta, the increased/thickened blood vessels in the placenta, and the unclear boundary between the placenta and the uterus. […] MRI technology can provide clearer and more accurate images, especially for soft tissue imaging.

• #3 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. […] 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. […] Approximately 20% of previas will resolve prior to delivery, through so called placental migration. […] As placenta accreta usually presents in conjunction with placenta previa, the diagnosis is most often made by ultrasonography, either as part of routine antenatal testing or due to vaginal bleeding in the second or third trimester. […] Placenta previa is a potentially life-threatening diagnosis often complicated by accreta.

• #3

  https://link.springer.com/article/10.1007/s44196-023-00237-2

  Objective To analyze the diagnostic value of MRI in placenta previa. […] MRI examination is an important way for clinical diagnosis of placenta previa, and it is worth popularizing. […] The detection rate of central type, marginal type and partial type in group A was higher than that in group B. […] With surgery and pathology as the gold standard, the diagnostic accuracy and sensitivity of group A were higher than that of group B, and the rate of missed diagnosis was lower than that of group B. […] There were differences in the imaging manifestations of the pregnant women, such as the uneven signal in the placenta, the increased/thickened blood vessels in the placenta, and the unclear boundary between the placenta and the uterus. […] MRI technology can provide clearer and more accurate images, especially for soft tissue imaging.

• #3 Placenta previa | Radiology Reference Article | Radiopaedia.org

  https://radiopaedia.org/articles/placenta-praevia?lang=us

  Placenta previa is an abnormally low-lying placenta covering the internal cervical os. As a common cause of antepartum hemorrhage, placenta previa is a potentially life-threatening condition for both mother and infant. As such, antenatal diagnosis is essential to prepare for childbirth adequately. […] Due to placental trophotropism, the diagnosis of a placenta previa is not made before 16 weeks. […] A low-lying placenta is relatively common in the second-trimester morphology scan, as the fetus grows and the uterus expands, the lower uterine segment thins and grows at a faster rate, such that in most cases the placenta is no longer low-lying by a follow-up transabdominal ultrasound. In asymptomatic women, this is recommended at 32 weeks, and if the placenta is persistently low-lying (including placenta previa), a further follow-up transvaginal ultrasound is recommended at 36 weeks.

• #3 Placenta Previa and Low Lying Placenta – London Pregnancy Clinic

  https://www.londonpregnancy.com/placenta-previa/

  Placenta previa, also known as a low-lying placenta, is a condition in pregnancy where the placenta attaches lower in the womb than usual, often covering or being close to the cervix (the opening to the birth canal). This placement can cause issues, especially as the cervix starts to thin and open later in pregnancy. […] Placenta previa is usually diagnosed during the routine 20-week anatomy scan, where a detailed ultrasound can reveal the placentas location. The scan allows the sonographer or obstetrician to assess whether the placenta is low-lying and if it partially or fully covers the cervix. […] If placenta previa is detected, additional scans may be scheduled throughout the pregnancy to monitor whether the placenta moves upwards as the uterus expands. […] Regular follow-up scans in the third trimester are essential to monitor any changes and to assess whether a caesarean delivery may be necessary.

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