Placenta Previa

What is Placenta Previa?

Placenta Previa is a condition that is considered to be a pregnancy complication. The placenta is the fluid and nutrient filled sac that surrounds the fetus as it grows and develops. When a pregnant woman develops placenta previa, it means that the placenta has grown in such a way that it covers the opening of the cervix. The placenta may cover all or just a part of the cervix.

In a “normal” pregnancy, the placenta attaches itself higher in the uterus so that it will not block the opening of the cervix. Placenta previa involves an abnormally low placenta later in a woman’s pregnancy. It is quite normal during early pregnancy for the placenta to be lower in the uterus, but as the pregnancy progresses, the placenta generally moves up in uterus leaving the cervix and the birth canal unobstructed.

There are many potential causes for placenta previa. If a woman has a uterus that is not normally shaped (either due to genetics or from scar tissue from previous cesarean deliveries or uterine surgeries), they may be more likely to suffer placenta previa. A woman who has had numerous other children, is pregnant with more than one child, or is pregnant through the assistance of in vitro fertilization may also be more prone to placenta previa.

What are the Symptoms of Placenta Previa?

Sometimes, placenta previa causes no symptoms at all. However, the most common symptoms of the condition are cramping and vaginal bleeding. This vaginal bleeding may be severe and usually occurs at the end of the second trimester or beginning of the third. The bleeding may stop on its own and return at a later time or may be continuous. Vaginal bleeding to placenta previa may be life-threatening.

How is Placenta Previa Treated?

Because a placenta previa blocks the birth canal, there is a high risk of heavy bleeding during delivery that could be life-threatening to mother and child both. As such, a cesarean delivery is often necessary. If the condition is detected via ultrasound before labor begins, a doctor may recommend a scheduled cesarean after 36 weeks of pregnancy. Also, when a placenta previa is detected early, bed rest and reduced activities, and even hospitalization or medications and blood transfusions may be necessary.

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Last Reviewed:
October 08, 2016
Last Updated:
August 28, 2017