Placenta Previa

Placenta previa is a condition in which the placenta implants in the lower part of the uterus in pregnant women. The placenta either partially or completely covers the opening to the cervix. This is a problem because the baby must pass through the cervix during delivery. There are three types of placenta previa:

• Marginal placenta previa. The placenta reaches within an inch (2.5 cm) of the cervical opening but does not cover it.
• Partial placenta previa. The placenta covers part of the cervical opening.
• Complete placenta previa. The placenta covers the entire cervical opening.

If the previa is marginal or partial and it is diagnosed in the first half of pregnancy, the placenta may move into a normal position as the pregnancy progresses and may no longer cover the cervix. It is important to keep all prenatal visits with your health care provider so you can be more closely monitored.

What are the causes?

The cause of this condition is not known.

What increases the risk?

This condition is more likely to develop in women who:

• Are carrying more than one baby (multiples).
• Have an abnormally shaped uterus.
• Have scars on the lining of the uterus.
• Have had surgeries involving the uterus, such as a cesarean delivery.
• Have delivered a baby before.
• Have a history of placenta previa.
• Have smoked or used cocaine during pregnancy.
• Are age 35 or older during pregnancy.

What are the signs or symptoms?

The main symptom of this condition is sudden, painless vaginal bleeding during the second half of pregnancy. The amount of bleeding can be very light at first, and it usually stops on its own. Heavier bleeding episodes may also happen. Some women with placenta previa may have no bleeding at all.

How is this diagnosed?

• This condition is diagnosed:
  • From an ultrasound. This test uses sound waves to find where the placenta is located before you have any bleeding episodes.
  • During a checkup after vaginal bleeding is noticed.
• If you are diagnosed with a partial or complete previa, digital exams with fingers will generally be avoided. Your health care provider will still perform a speculum exam.
• If you did not have an ultrasound during your pregnancy, placenta previa may not be diagnosed until bleeding occurs during labor.

How is this treated?

Treatment for this condition may include:

• Decreased activity.
• Bed rest at home or in the hospital.
• Pelvic rest. Nothing is placed inside the vagina during pelvic rest. This means not having sex and not using tampons or douches.
• A blood transfusion to replace blood that you have lost (maternal blood loss).
• A cesarean delivery. This may be performed if:
  • The bleeding is heavy and cannot be controlled.
  • The placenta completely covers the cervix.
• Medicines to stop premature labor or to help the baby’s lungs to mature. This treatment may be used if you need delivery before your pregnancy is full-term.

Your treatment will be decided based on:

• How much you are bleeding, or whether the bleeding has stopped.
• How far along you are in your pregnancy.
• The condition of your baby.
• The type of placenta previa that you have.

Follow these instructions at home:

• Get plenty of rest and lessen activity as told by your health care provider.
• Stay on bed rest for as long as told by your health care provider.
• Do not have sex, use tampons, use a douche, or place anything inside of your vagina if your health care provider recommended pelvic rest.
• Take over-the-counter and prescription medicines as told by your health care provider.
• Keep all follow-up visits as told by your health care provider. This is important.

Get help right away if:

• You have vaginal bleeding, even if in small amounts and even if you have no pain.
• You have cramping or regular contractions.
• You have pain in your abdomen or your lower back.
• You have a feeling of increased pressure in your pelvis.
• You have increased watery or bloody mucus from the vagina.