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, including 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 myomectomy (removal of uterine fibroids through an incision in the uterus)
Previous cesarean section (if the scar is low and close to the vaginal cervix)
Diagnosing the problem
Placenta previa can cause painless bleeding during the second or third trimester. If this happens, an ultrasound test 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, the following treatments may be recommended:
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 immediately if bleeding cannot be stopped)
Even if you are not on bed rest, your healthcare provider may ask you to restrict your activity. You will likely be told to:
Avoid pelvic exams
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 try the Internet.
March 03, 2018
Clinical Features, Diagnosis, and Course of Placenta Previa. UpToDate, Management of Placenta Previa. UpToDate
Burd, Irina, MD, PhD,Freeborn, Donna, PhD, CNM, FNP,Image reviewed by StayWell medical illustration team.