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Placenta Previa

Placenta previa is a condition that may happen during the second or third trimester of pregnancy. It's one of the most common causes of vaginal bleeding during these trimesters. It happens when the placenta implants in the lower part of the uterus. This causes the placenta to block part or all of the opening of the cervix to the vagina (birth canal). It can lead to problems for both the mother and baby. This can include blood loss and premature labor.

Some factors that make placenta previa more likely

Factors include the following:

  • Multiple pregnancy (carrying more than one baby)

  • Previous pregnancies and deliveries

  • Previous removal of uterine fibroids through an incision in the uterus (myomectomy)

  • Previous cesarean section (if the scar is low and close to the vaginal cervix)

  • Smoking cigarettes

Diagnosing the problem

Placenta previa can cause painless bleeding during the second or third trimester. If this happens, an ultrasound can confirm the problem. But the problem can be present without bleeding. So your healthcare provider will check the position of the placenta during routine ultrasound exams.

Treating the problem

Depending on the amount of bleeding, the type of placenta previa, and the stage of the pregnancy, these treatments may be advised:

  • Partial or complete bed rest for the mother

  • Blood transfusions to replace maternal blood loss

  • Medicines to help mature the baby’s lungs or prevent premature labor

  • Cesarean delivery (this may be done right away if bleeding can't be stopped)

During treatment

Even if you aren't on bed rest, your healthcare provider may restrict your activity. You will likely be told:

  • Not to have sex

  • Limit travel

  • Not to have pelvic exams

Getting support

It may be frustrating and frightening to be diagnosed with a problem during pregnancy. It may help to join a support group for women who are going through the same problem. Ask your healthcare provider to help you find a support group in your area. Or look for one online.

Online Medical Reviewer: Donna Freeborn PhD CNM FNP
Online Medical Reviewer: Heather Trevino
Online Medical Reviewer: Irina Burd MD PhD
Date Last Reviewed: 2/1/2020
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