Placenta Previa

What is placenta previa?

Placenta previa is a placenta that lies below the baby in the uterus during pregnancy. In this position, the placenta may cover all or part of the opening of the uterus (cervix).

The placenta develops in the uterus during pregnancy. It lets oxygen, nourishment, and wastes pass between the mother and the baby.

Placenta previa can cause severe bleeding and can be very serious for the mother and baby. It happens in less than 1% of pregnancies.

How does it occur?

Placenta previa happens when the fertilized egg attaches to the lower part of the uterus instead of the top or sides of the uterus. This can result in a placenta that is over the cervix. Often, as the uterus grows during the first 3 months of pregnancy, the placenta moves away from the opening of the uterus. If the placenta does not move up and out of the way, it is called previa.

Some women have a higher risk for this problem than others. The risk is higher for women who:

• are older than 35
• are smokers
• have had more than 1 previous delivery
• have had many terminations of pregnancy (also called abortions)
• are carrying twins
• have had a C-section
• have had placenta previa before

What are the symptoms?

Heavy, bright red, painless bleeding from the vagina that begins suddenly in the last few months of pregnancy may be a sign of placenta previa. Sometimes the bleeding can be confused with a type of light bleeding that can happen during normal labor, called the bloody show. There is usually no pain, tenderness, uterine contractions, or cramps.

How is it diagnosed?

Tests that may be done are:

• ultrasound scan
• blood tests
• double setup exam if there is no time for an ultrasound or ultrasound is not available (A double setup exam is an exam of the cervix with a speculum in the operating room. Your healthcare provider will be ready to do a C-section if necessary.)

How is it treated?

Treatment depends on how much bleeding you have had and how far along you are in the pregnancy.

If it is before 37 weeks in the pregnancy and you have not lost a lot of blood, your healthcare provider may recommend or prescribe:

• bed rest or staying in the hospital
• iron pills or a blood transfusion if your blood count is too low
• a drug to stop contractions if the bleeding is caused by contractions of the uterus

You may need ultrasound tests every 1 to 4 weeks. Nonstress tests or biophysical profiles may also be done to make sure the baby is doing well.

If you have lost a lot of blood, you may need a blood transfusion. The baby may need to be delivered early. The decision to deliver the baby will depend on how close you are to your due date and on how heavy the bleeding is. If you have severe bleeding, the baby is usually delivered surgically by C-section (cesarean section) as soon as possible to save your life and the baby.

If you start having bleeding after 37 weeks of pregnancy and the placenta does not completely cover the opening to the uterus, your healthcare provider may let you go into labor and try a vaginal delivery. You will be monitored closely. At the first sign of increased bleeding you may need a C-section to deliver the baby. If the placenta does completely cover the opening of the uterus, a C-section is the only way to deliver the baby safely.

How long will the effects last?

In some cases, placenta previa may keep the baby from getting enough nutrients and oxygen for normal growth. This causes the baby to grow more slowly. This is called intrauterine growth restriction (IUGR).

How can I take care of myself?

• To prevent bleeding when you have placenta previa, limit your regular activity or rest in bed.
• Don’t put anything into your vagina, such as a tampon, because it may cause more bleeding.
• Don’t have sex.
• Don’t smoke.
• If your healthcare provider prescribes iron, be sure you take it. It is best to take iron with meals so it will not upset your stomach.
• Avoid a lot of bending and lifting.
• Tell your provider if you have any pain, contractions, or bleeding.

What can be done to help prevent placenta previa?

There is no way to prevent placenta previa.