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Placenta Accreta


Julie S. Moldenhauer

, MD, Children's Hospital of Philadelphia

Reviewed/Revised Jan 2024

Placenta accreta is a placenta with an abnormally firm attachment to the uterus.

After delivery of the baby, the placenta usually detaches from the uterus, and a woman can push the placenta out by herself or with help from a doctor or midwife. When the placenta is too firmly attached, parts of the placenta may remain in the uterus after delivery. In these cases, delivery of the placenta is delayed, and the risks of bleeding and infection in the uterus are increased. Bleeding may be life threatening.

In the United States, rates of cesarean delivery have increased, and therefore rates of placenta accreta has also been increasing.

Risk factors

Diagnosis of Placenta Accreta

  • Ultrasonography

  • Sometimes magnetic resonance imaging (MRI)

If a woman has conditions that increase the risk of placenta accreta, doctors usually do ultrasonography before delivery to check for placenta accreta. Ultrasonography, using a handheld device placed on the abdomen or inside the vagina, may be done periodically, starting at about 20 to 24 weeks of pregnancy. If ultrasonography is unclear, MRI may be done.

During delivery, placenta accreta is suspected if any of the following occur:

  • The placenta has not been delivered within 30 minutes after the baby’s delivery.

  • Doctors cannot separate the placenta from the uterus by hand.

  • Attempting to remove the placenta results in profuse bleeding.

Treatment of Placenta Accreta

  • Cesarean hysterectomy

If doctors detect placenta accreta before delivery, a cesarean delivery Cesarean Delivery Cesarean delivery is surgical delivery of a baby by incision through a woman’s abdomen and uterus. In the United States, over 30% of deliveries are cesarean. Doctors use a cesarean delivery... read more Cesarean Delivery followed by removal of the uterus (cesarean hysterectomy) is typically done. For this procedure, the baby is first delivered by cesarean. Then the uterus is removed with the placenta in place. This procedure is usually done at about 34 weeks of pregnancy. It helps prevent potentially life-threatening loss of blood, which can occur when the placenta remains attached after delivery. However, the procedure can cause complications, such as profuse bleeding. Also, blood clots Blood clots Staying in bed for a long time without regular physical activity, as may occur in a hospital, can cause many problems. (See also Problems Due to Hospitalization.) A leg injury, leg surgery,... read more can develop if the surgery takes a long time and/or requires a long period of bed rest afterward. Blood clots can travel through the bloodstream and block an artery in the lungs (a condition called pulmonary embolism Pulmonary Embolism (PE) Pulmonary embolism is the blocking of an artery of the lung (pulmonary artery) by a collection of solid material brought through the bloodstream (embolus)—usually a blood clot (thrombus) or... read more ). A cesarean hysterectomy should be done by an experienced surgeon and at a hospital that is equipped to handle the complications.

If future childbearing is important to a woman, doctors try to preserve the uterus using various techniques. However, these techniques cannot be used if bleeding is extremely heavy or is likely to be extremely heavy (because of the placenta's location).

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