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Placenta Previa

Contact Maternal Fetal Medicine at UPMC-Magee Women's Hospital

To make an appointment with a maternal fetal medicine expert, call 412-641-6361.

What Is Placenta Previa?

Placenta previa is a condition where the placenta stays in the lower part of your uterus throughout your pregnancy. When this happens, the placenta might cover all or part of your cervix — the entrance to the birth canal.

It's normal for the placenta to lie near the cervix in the early part of pregnancy. As your baby grows, it moves higher, until it is further from the cervix by the third trimester.

But sometimes the placenta will stay too low. This increases your risk of severe bleeding during labor when the cervix dilates.

Placenta previa happens in about 1 out of 200 pregnancies.

Types of placenta previa

There are 2 types of placenta previa:

  • Partial previa — when the placenta partially blocks the cervix.
  • Complete — when the placenta fully covers the cervix.

As you near your due date, your cervix thins and widens so your baby can pass through.

If the placenta is too close to the cervix, blood vessels attached to it can tear. Any type of placenta previa can cause a hemorrhage in your third trimester or when you're in labor.

A low-lying placenta is one that is not blocking the cervix, but is within 2 cm of the cervix opening.

Cause of placenta previa

The exact cause of placenta previa is unknown.

It might be due to scarring or damage to the uterine lining from surgery on the uterus.

Placenta previa risk factors and complications

Some women are more likely to have placenta previa, such as those who:

  • Have had a previa in a prior pregnancy.
  • Have had a previous C-section.
  • Are carrying twins or other multiple pregnancies.
  • Are of an advanced age.
  • Smoke.
  • Have had IVF.

If you've had placenta previa in the past, there's a 4 to 8% chance you could have it again.

Placenta previa can cause life-threatening bleeding during labor.

More than likely, you'll need to have your baby by C-section.

Problems from placenta previa bleeding can include:

  • Extra blood loss and the need for a blood transfusion.
  • Admission to the ICU.
  • The need for a C-section with a hysterectomy (removal of your uterus), if the bleeding does not stop after delivery.

If you have to deliver early, placenta previa might also cause complications for your baby, such as:

  • A low birth weight.
  • Lower APGAR scores (a rating of your baby's color, heart rate, muscle tone, reflexes, and breathing).
  • Risk of respiratory distress syndrome if your baby's lungs haven't fully formed.

While you can't prevent this condition, you and your care team can manage it by optimizing your blood count throughout your pregnancy and being prepared for extra bleeding at delivery.

It's crucial to follow your doctor's advice about ways to reduce the risk of placenta previa bleeding.

Why Choose UPMC Magee-Women's Hospital for Placenta Previa Care?

UPMC's Division of Maternal Fetal Medicine brings a team of experts together to manage high-risk pregnancies, including placenta previa.

We also provide complete care throughout all stages of your pregnancy.

Placenta Previa Symptoms and Diagnosis

The main symptom of placenta previa is bright red bleeding in the later part of your pregnancy. It might start, stop, and then start again when you're in labor.

Many women have no placenta previa symptoms, but it can be diagnosed on ultrasound.

Placenta previa bleeding is usually painless, without contractions, but you might have cramps.

If you have any bleeding during your pregnancy, it's vital to call your doctor. If your bleeding is heavy, go to the ER right away.

Diagnosing placenta previa

Placenta previa is usually diagnosed during a routine prenatal ultrasound.

If you have bleeding during your pregnancy, you may need a transvaginal ultrasound. Your doctor will place the ultrasound wand into your vagina to get a closer look at your cervix and placenta position.

Your doctor might also order:

  • Blood tests to find out your blood type if you need a transfusion. Other blood tests check your blood count.

Placenta Previa Treatment

Treatment helps prevent serious bleeding and allows you to carry your baby to term — at least 36 weeks. Your MFM care team will work with you to weigh the risk of bleeding against the risk of delivering your baby early.

Placenta previa treatments might include:

  • Pelvic rest, which means not having sex or placing anything in your vagina.
  • Monitoring for bleeding and preterm labor.
  • Steroid shots to help your baby's lungs mature if there are concerns that an extra early delivery will be needed.
  • Medications to treat anemia.
  • A blood transfusion if significant bleeding occurs.
  • C-section delivery.