Short Answer – Placenta previa occurs when the placenta (the organ created during pregnancy that nourishes the fetus) lies unusually low in the uterus, either partly or completely blocking the cervix. Placenta previa usually resolves on its own, but if it progresses to later stages of the pregnancy it can cause bleeding or other complications, so a cesarean section may be required.

If the placenta is completely covering the cervix, it’s called a complete of total previa. If the placenta is on the border of the cervix, it’s called a marginal or partial previa.

Placenta previa discovered early in pregnancy is not all that uncommon and not generally considered a problem. As your pregnancy progresses, your placenta will likely migrate away from your cervix and no longer be an issue. Only 10% of placenta previa cases (about 1 in 200) persist later in pregnancy.

What Happens If I am Diagnosed With Placenta Previa?

First off, don’t panic. Like we said, as the uterus grows the placenta will often move higher correcting the condition on its own.  

But if a follow-up ultrasound later in pregnancy reveals your placenta is still too close to the cervix, you will most likely be put on pelvic rest. This means you cannot have intercourse or vaginal exams for the duration of your pregnancy. You’ll also be advised to relax and avoid strenuous activity.

If the previa condition still exists close to the time of delivery, you’ll need a c-section. Previa puts you at risk for serious bleeding as the cervix dilates. For this reason, women with placenta previa usually deliver by cesarean before their due date (to avoid dilation).

In addition, due to the increased chance of heavy bleeding, you may need a blood transfusion during or after delivery. Your doctor will discuss the risks and protocols with you prior to your c-section.