Trusted, evidence-based resources for women navigating placenta previa, placenta accreta spectrum, and related maternal complications. Know your options, understand your risks, and connect with specialists.
Understanding monitoring, activity restrictions, and delivery planning with your care team.
Specialist-reviewed content updated regularly
Learn about the two primary placental complications, their symptoms, diagnosis methods, and management strategies recommended by maternal-fetal medicine specialists.
A condition where the placenta partially or completely covers the cervical opening (os). This can cause painless vaginal bleeding, particularly in the third trimester, and typically requires cesarean delivery.
A group of conditions (accreta, increta, percreta) where the placenta abnormally attaches too deeply into the uterine wall. Often associated with prior C-sections, it carries a higher risk of major hemorrhage.
Placenta previa often has no symptoms early on, but key warning signs include:
Painless vaginal bleeding — especially in 2nd or 3rd trimester
Bright red bleeding — can begin suddenly without warning
Uterine cramping — especially after bleeding episodes
Breech or transverse position — baby may not be head-down
Recurring bleeding — episodes may stop and restart
Large uterus for gestational age — less common indicator
Note: Some women have no bleeding at all. Previa is often diagnosed via routine ultrasound.
Placenta previa is diagnosed using imaging. The standard diagnostic pathway involves:
Transvaginal ultrasound — most accurate method for placental localization
Transabdominal ultrasound — often used first; may miss low-lying placenta
MRI — used when ultrasound is inconclusive or accreta is suspected
Follow-up scans at 32–36 weeks — ~90% of low-lying placentas resolve by term
Management depends on gestational age, symptoms, and degree of previa:
Pelvic rest — no intercourse, tampons, or pelvic exams
Activity restriction — reduced physical exertion; sometimes bed rest
Regular monitoring — ultrasound every 2–4 weeks in 3rd trimester
Corticosteroids — if preterm delivery is anticipated to mature fetal lungs
Hospitalization — for heavy bleeding or if far from medical care
Planned cesarean — typically at 36–37 weeks; earlier if bleeding persists
Placenta accreta spectrum (PAS) is often asymptomatic during pregnancy. Risk factors and signs include:
Prior cesarean delivery — #1 risk factor; risk increases with each C-section
Prior uterine surgery — myomectomy, D&C, endometrial ablation, or any procedure that scars the uterine wall
Low-lying or previa placenta — PAS very common when previa overlies a uterine scar
IVF / frozen embryo transfer — research shows significantly elevated PAS risk, especially with hormone replacement cycles
Abnormal 3rd trimester bleeding — may indicate partial abruption
Difficulty with placental delivery — often first recognized at time of birth
Elevated AFP — abnormal maternal serum screening result may prompt further workup
PAS requires a highly specialized, multidisciplinary approach. Management typically involves:
Delivery at a PAS Center of Excellence — hospitals with dedicated multidisciplinary teams
MFM + surgical specialists — OB, urology, vascular surgery, and interventional radiology
Cell salvage and transfusion readiness — large blood loss is expected
Planned hysterectomy — typically recommended to prevent life-threatening hemorrhage
Delivery at 34–36 weeks — planned preterm birth reduces emergency risk
Counseling on fertility — hysterectomy ends future pregnancies; discussion is essential
Curated links to reputable medical organizations, patient guides, and research resources to support your care decisions.
The American College of Obstetricians and Gynecologists provides a comprehensive patient-facing FAQ on placenta previa, covering causes, symptoms, and treatment.
Clinical guidance from ACOG on the management of placenta accreta spectrum disorders, including diagnosis, delivery planning, and surgical approaches.
The National Institute of Child Health and Human Development offers a medically reviewed overview of placenta previa with information on risk factors and outcomes.
A patient-led nonprofit dedicated to placenta accreta spectrum awareness, connecting patients with centers of excellence and providing support networks for survivors.
Comprehensive patient resource from Mayo Clinic covering symptoms, causes, diagnosis, treatment, and what to expect during delivery with placenta previa.
Evidence-based clinical decision support on managing placenta previa, including antepartum care, delivery timing, and surgical considerations. (Subscription may be required.)
SMFM is the leading organization for MFM specialists. Their website includes patient resources, guidelines, and a provider locator to find high-risk pregnancy specialists near you.
Johns Hopkins Medicine's patient education resource on placenta accreta, covering the spectrum of severity (accreta, increta, percreta) and their distinct management approaches.
Search thousands of peer-reviewed studies on placenta accreta spectrum. Useful for patients who want to understand the latest clinical evidence and discuss options with their care team.
Managing placental complications requires a coordinated team of experts. Here's who you might encounter and what role each plays in your care.
Your primary specialist for high-risk pregnancy management. An MFM physician oversees diagnosis, monitoring, and overall care planning for placenta previa and accreta spectrum. They coordinate the multidisciplinary team and guide delivery decisions.
In cases of placenta accreta, an interventional radiologist may place balloon catheters in uterine arteries before delivery to reduce blood loss. They can also perform uterine artery embolization if hemorrhage occurs postpartum.
A specialized obstetric anesthesiologist manages pain control and hemodynamic stability during what may be a complex and lengthy surgical delivery. They monitor blood pressure, transfusions, and recovery in cases involving significant blood loss.
For placenta percreta (the most severe form of PAS), a gynecologic oncologist or pelvic reconstructive surgeon may assist with hysterectomy and repair of adjacent structures like the bladder or bowel that may be involved.