Overview

Placenta accreta is a serious pregnancy condition that occurs when blood vessels and other parts of the placenta grow too deeply into the uterine wall.

Typically, the placenta detaches from the uterine wall after childbirth. With placenta accreta, part or all of the placenta remains firmly attached. This can cause severe blood loss after delivery.

It's also possible for the placenta to invade the muscles of the uterus (placenta increta) or grow through the uterine wall (placenta percreta).

Placenta accreta is considered a high-risk pregnancy complication. If placenta accreta is suspected during pregnancy, you'll likely need an early C-section delivery followed by the surgical removal of your uterus (hysterectomy).

Symptoms

Placenta accreta often causes no signs or symptoms during pregnancy — although vaginal bleeding during the third trimester is possible. Often, placenta accreta is detected during a routine ultrasound.

If you experience vaginal bleeding during your third trimester, contact your health care provider right away. If the bleeding is severe, seek emergency care.

Causes

Placenta accreta is thought to be related to abnormalities in the lining of the uterus, typically due to scarring after a C-section or other uterine surgery. This might allow the placenta to grow too deeply into the uterine wall. Sometimes, however, placenta accreta occurs without a history of uterine surgery.

Risk factors

Many factors can increase the risk of placenta accreta, including:

  • Previous uterine surgery. If you've had a C-section or other uterine surgery, you're at increased risk of placenta accreta. The risk of placenta accreta increases with the number of uterine surgeries.
  • Placenta position. If your placenta partially or totally covers your cervix (placenta previa) or sits in the lower portion of your uterus, you're at increased risk of placenta accreta.
  • Maternal age. Placenta accreta is more common in women older than 35.
  • Previous childbirth. The risk of placenta accreta increases each time you give birth.
  • Uterine conditions. The risk of placenta accreta is higher if you have abnormalities or scarring in the tissue that lines your uterus (endometrium). Noncancerous uterine growths that bulge into the uterine cavity (submucosal uterine fibroids) also increase the risk.

Complications

Placenta accreta can cause serious complications, including:

  • Heavy vaginal bleeding. Placenta accreta poses a major risk of severe vaginal bleeding (hemorrhage) after delivery. The bleeding can cause a life-threatening condition that prevents your blood from clotting normally (disseminated intravascular coagulopathy), as well as lung failure (adult respiratory distress syndrome) and kidney failure. A blood transfusion will probably be necessary.
  • Premature birth. Placenta accrete might cause labor to begin early. If placenta accreta causes bleeding during your pregnancy, you might need to deliver your baby early.
March 28, 2015
References
  1. Wortman AC, et al. Placenta accreta, increta, and percreta. Obstetrics and Gynecology Clinics of North America. 2013;40:137.
  2. Creasy RK, et al. Placenta previa, placenta accreta, abruptio placentae, and vasa previa. In: Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 7th ed. Philadelphia, Pa.: Saunders Elsevier; 2014. http://www.clinicalkey.com. Accessed Feb. 3, 2015.
  3. Cunningham FG, et al. Placental abnormalities. In: Williams Obstetrics. 24th ed. New York, N.Y.: The McGraw-Hill Companies; 2014. http://www.accessmedicine.com. Accessed Feb. 3, 2015.
  4. Resnik R. Clinical features and diagnosis of placenta accreta, increta, and percreta. http://www.uptodate.com/home. Accessed Feb. 4, 2015.
  5. Eshkoli T, et al. Placenta accreta: Risk factors, perinatal outcomes, and consequences for subsequent births. American Journal of Obstetrics and Gynecology. 2013;208:219e1.
  6. Resnik R. Management of placenta accreta, increta, and percreta. http://www.uptodate.com/home. Accessed Feb. 4, 2015.
  7. Legendre G, et al. Conservative management of placenta accreta: Hysteroscopic resection of retained tissues. The Journal of Minimally Invasive Gynecology. 2014;21:910.
  8. Relaxation techniques for health: An introduction. National Center for Complementary and Integrative Health. https://nccih.nih.gov/health/stress/relaxation.htm. Accessed Feb. 5, 2015.
  9. Wick MJ (expert opinion). Mayo Clinic, Rochester, Minn. Feb. 19, 2015.