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What is Placenta Previa?

Placenta previa refers to a condition of pregnancy in which the placenta is implanted below the baby in the uterus. It is usually described one of three different ways:

Marginal Previa: The placenta is implanted near the cervix.

Partial Previa: The placenta is touching or partially covering the cervix.

Total Previa: The placenta is completely covering the cervix.

Although a large percentage of women will have a low-lying placenta early in pregnancy, only about .5% of women are diagnosed with placenta previa in pregnancy. Normally, the placenta will move up and out as the uterus expands. The diagnosis of placenta previa is not usually made until the third trimester. The first sign of previa is most likely to be painless spotting or bleeding because part of the placenta begins to break away from the uterine wall as the uterus expands. When spotting or bleeding occurs, previa can be tested for with an ultrasound or a blood test. There are no known preventive measures against placenta previa.

What are the risk factors?

Over 35
More than one previous delivery
Previous abortions
Previous cesarean section
Previous previa

What are the dangers?

Placenta previa is dangerous for both the mother and child due to the increased risk for hemorrhage. Most women with placenta previa will require a cesarean section to safely deliver the baby.
What does a diagnosis mean?

In most cases a diagnosis of placenta previa means bed rest or at least lying down as much as possible if a woman is less than 37 weeks. It can mean a hospital stay for those who need to be monitored closely or live too far from the hospital. Measures are taken to prolong the pregnancy as long as possible to allow time for the baby's lungs to fully develop. If necessary, steroid shots may be given to help the lungs mature. The woman may need blood transfusions due to the loss of blood while labor is prevented as long as possible. Doctors suggest that women abstain from sexual intercourse, lie down as much as possible, and take iron supplements once diagnosed with placenta previa. There are online support groups for bedrest moms and mothers with placenta previa.