Mayo Clinic Health Library

Placenta accreta

Updated: 05-24-2012

Definition

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.

The placenta is a structure that develops in the uterus during pregnancy. The placenta provides oxygen and nutrients to your growing baby and removes waste products from your baby's blood. It attaches to the wall of your uterus, and your baby's umbilical cord arises from it.

Typically, the placenta detaches from the uterine wall after childbirth. With placenta accreta, part or all of the placenta remains strongly attached. This can cause vaginal bleeding during the third trimester of pregnancy and 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).

If extensive placenta accreta is suspected during pregnancy, you'll likely need a C-section delivery followed by the surgical removal of your uterus (hysterectomy).

Next

Symptoms

Placenta accreta often causes no symptoms during pregnancy — although vaginal bleeding during the third trimester is possible.

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

PreviousNext

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.

PreviousNext

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.
PreviousNext

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.
  • Premature birth. If you have placenta accreta, you might begin labor early. If placenta accreta causes bleeding during your pregnancy, you might need to deliver your baby early.
PreviousNext

Preparing for your appointment

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

Often, placenta accreta is suspected after an ultrasound early in pregnancy. A follow-up visit can give you an opportunity to find out about the condition and develop a plan to manage it.

What you can do
Before your appointment, you might want to:

  • Ask about pre-appointment restrictions. In most cases, you'll be seen immediately. If your appointment will be delayed, ask whether you should restrict your activity in the meantime.
  • Ask a loved one or friend to join you for the appointment. Fear and anxiety might make it difficult to focus on what your health care provider says. Take someone along who can help you remember all the information.
  • Write down questions to ask your health care provider. That way, you won't forget anything important that you want to ask, and you can make the most of your time with your health care provider.

Below are some basic questions to ask your health care provider about placenta accreta:

  • What's causing the bleeding?
  • What treatment approach do you recommend?
  • What follow-up care will I need during the rest of my pregnancy?
  • What signs or symptoms should cause me to call you?
  • What signs or symptoms should cause me to go to the hospital?
  • Will I be able to deliver vaginally?
  • Does this condition increase the risk of complications during future pregnancies?
  • Will I need to have a hysterectomy after the baby is born?

In addition to the questions you've prepared, don't hesitate to ask other questions during your appointment — especially if you need clarification or you don't understand something.

What to expect from your doctor
Your health care provider is likely to ask you a number of questions, too. For example:

  • When did you first notice vaginal bleeding?
  • Did you bleed only once, or has the bleeding come and gone?
  • How heavy is the bleeding?
  • Is the bleeding accompanied by pain or contractions?
  • Have you had any previous pregnancies that I'm not aware of?
  • Have you had any uterine surgeries that I'm not aware of?
  • How long would it take to get to the hospital in an emergency, including time to arrange child care and transportation?
PreviousNext

Tests and diagnosis

If you have risk factors for placenta accreta during pregnancy — such as the placenta partially or totally covering the cervix (placenta previa) or a previous uterine surgery — your health care provider will carefully examine the implantation of your baby's placenta.

Techniques to help diagnose placenta accreta might include:

  • Imaging tests. Your health care provider might use ultrasound or magnetic resonance imaging (MRI) to evaluate how the placenta is implanted in your uterine wall.
  • Blood tests. Your health care provider might test a sample of your blood for an otherwise unexplained rise in the amount of alpha fetoprotein — a protein that's produced by the baby and can be detected in the mother's blood. Such a rise has been linked to placenta accreta.
PreviousNext

Treatments and drugs

If your health care provider suspects placenta accreta, he or she will work with you to develop a plan to safely deliver your baby.

In the case of extensive placenta accreta, a C-section followed by the surgical removal of the uterus (hysterectomy) might be necessary. This procedure, also called a cesarean hysterectomy, helps prevent the potentially life-threatening blood loss that can occur if part or all of the placenta remains attached after delivery.

A cesarean hysterectomy should be done at a hospital that has an intensive care unit and is equipped to handle complications, such as severe bleeding. Your health care team for the surgery might include an obstetrical surgeon, a pelvic surgeon and an anesthesiologist, as well as a neonatologist to treat your baby.

Your health care provider might recommend scheduling the C-section and hysterectomy as early as week 35 of pregnancy to avoid an unscheduled delivery. To evaluate the maturity of your baby's lungs, your health care provider might test a sample of amniotic fluid — the fluid that surrounds and protects a baby during pregnancy. This test is known as maturity amniocentesis.

During the C-section, your health care provider will deliver your baby through an incision in your abdomen and a second incision in your uterus. After delivering your baby, your health care provider or another member of your health care team will remove your uterus — with the placenta still attached — to prevent severe bleeding.

A hysterectomy ends your ability to become pregnant. If you had planned to become pregnant again in the future, consult your health care provider.

Rarely, the uterus and placenta might be allowed to remain intact, allowing the placenta to dissolve over time. However, this approach can have serious complications, including:

  • Severe vaginal bleeding
  • Infection
  • A blood clot that blocks one or more arteries in the lungs (pulmonary embolism)
  • The need for a hysterectomy at a later date

In addition, limited research suggests that women who are able to avoid hysterectomy after having placenta accreta are at risk of pregnancy complications with subsequent pregnancies, including miscarriage, premature birth and recurrent placenta accreta.

If you're interested in uterine conservation, ask your health care provider if it's a possibility for you. If so, he or she can help you weigh the risks and benefits.

PreviousNext

Coping and support

If your health care provider suspects that you have placenta accreta, you're likely worried about how your condition will affect your delivery, your baby and, possibly, your ability to become pregnant in the future.

To ease your anxiety:

  • Find out about placenta accreta. Gathering information about your condition might help you feel less anxious. Talk to your health care provider, do some research and connect with other women who've had placenta accreta.
  • Prepare for a C-section. If you're disappointed that you won't be able to have a vaginal birth, remind yourself that your baby's health and your health are more important than the method of delivery.
  • Prepare for a hysterectomy. After the hysterectomy, you'll no longer have periods or be able to get pregnant. This might lead to a deep sense of loss. Consult your health care provider about what to expect during your recovery. If you need help coping with feelings of grief or depression, consult a mental health provider.
  • Find healthy ways to relax. Set aside time for soothing activities, such as imagining pleasant objects or experiences.
Previous