What Is a Partial Placenta Previa?

Partial placenta previa is a complication that can occur during pregnancy when the placenta moves lower in the uterus and covers a portion of the cervix. The condition affects one out of every 200 pregnant women and typically occurs during the third trimester. Women who have had previous pregnancies, have had a prior Cesarean section, are 35 or older or are carrying multiple fetuses are more likely to develop partial placenta previa. Common causes include a large placenta, scars or abnormalities in the lining of the uterus and a uterus that is abnormally shaped.

The main symptom of partial placenta previa is painless vaginal bleeding. Pregnant women should seek medical attention anytime they experience bleeding. Light spotting during the first trimester is not usually caused by placenta previa. Light-to-heavy bleeding during the second and third trimesters could point to a placenta problem, and it might stop and restart intermittently.

Routine ultrasounds might find placenta previa before a woman has experienced any symptoms. Doctors also use ultrasounds to locate the placenta and diagnose any abnormalities after a pregnant woman has experienced vaginal bleeding. The fetus usually is not at severe risk at the time of diagnosis, as long as the woman seeks prompt care after noticing bleeding.

Women who have been diagnosed with partial placenta previa often require bed rest to prevent the placenta from dropping further into the uterus and covering all of the cervix. Bed rest usually is sufficient to control partial placenta previa, and mothers who have been diagnosed with this condition can often have a vaginal birth as long as they do not experience heavy bleeding and the placenta does not drop further into the uterus. Placenta problems accompanied by heavy bleeding often require the mother to rest in the hospital in case she needs a blood transfusion. Medications to stall premature labor might also be given to women who have heavy bleeding, and those women usually have to deliver via Cesarean section.

It is important for women who have been diagnosed with partial placenta previa to follow their doctor's instructions regarding bed rest and physical activity. Lying down helps keep the uterus stable, and women who have this condition should avoid sitting or standing as much as possible, particularly for long periods of time. Sexual intercourse might also worsen the problem, so pregnant women who have this condition might be advised to abstain from sexual activity until after the birth.

Mothers who have partial placenta previa are monitored carefully following a vaginal birth or Cesarean section. They might experience bleeding after delivery and might require medication or blood transfusions. In rare cases, the woman's uterus might need to be surgically removed if the placenta does not detach from the uterus after birth.