What is placental abruption?
Placental abruption is a pregnancy problem in which the placenta separates too early from the wall of the uterus. The placenta is a round, flat organ that forms during pregnancy. It gives the baby food and oxygen from your body.
- In a normal pregnancy, the placenta stays firmly attached to the inside wall of the uterus until after the baby is born.
- In placental abruption, the placenta breaks away (abrupts) from the wall of the uterus too early, before the baby is born.
Placental abruption can be very harmful. In rare cases, it can be deadly.
- Your baby may be born too early (premature) or at a low birth weight.
- You may lose a lot of blood.
Placental abruption usually occurs in the third trimester. But it can happen at any time after the 20th week of pregnancy.
What causes it?
Doctors aren't sure what causes it, but some things can raise your risk. These are called risk factors. Common risk factors for placental abruption include:
- High blood pressure. This is the biggest risk factor for placental abruption, whether the high blood pressure is a long-term problem or is caused by the pregnancy (preeclampsia).
- Having had placental abruption before.
- Smoking during pregnancy.
Less common risk factors include:
- Using cocaine.
- Having a scar from a past surgery or a uterine fibroid where the placenta has attached to the wall of the uterus.
- Having an injury to the uterus. This could occur because of a car accident, a fall, or physical abuse.
- Prelabor rupture of membranes for 24 hours or more, especially when there is an infection in the uterus.
What are the symptoms?
If you have placental abruption, you may notice one or more warning signs. Call your doctor right away if you are pregnant and you:
- Have light to moderate bleeding from your vagina.
- Have a painful or sore uterus. It might also feel hard or rigid.
- Have signs of early labor. These include regular contractions and aches or pains in your lower back or belly.
- Notice that your baby is moving less than usual.
You can't really tell how serious placental abruption is by the amount of vaginal bleeding. Sometimes the blood gets trapped between the placenta and the wall of the uterus. So there might be a serious problem even if there is only a little bleeding.
More serious symptoms include:
- Sudden or severe pain in your belly.
- Severe vaginal bleeding, such as a gush of blood or passing a clot.
- Any symptoms of shock. These include feeling lightheaded or like you are going faint; feeling confused, restless, or weak; feeling sick to your stomach or vomiting; and having fast, shallow breathing.
In rare cases, symptoms of shock are the only signs of a serious problem.
How is it diagnosed?
This problem can be hard to diagnose. Your doctor will ask questions about your symptoms and do a physical exam. Tests that may be done include:
- Fetal heart monitoring. This is to assess your baby's condition and check for contractions of the uterus.
- An ultrasound. This test can detect about half of placental abruptions.
- A blood test for anemia. You can become anemic from heavy blood loss.
If placental abruption is suspected, you'll probably need to be in the hospital until your doctor finds out how severe it is.
How is placental abruption treated?
The kind of treatment you need will depend on:
- How severe the abruption is.
- How it is affecting your baby.
- How close your due date is.
If you have mild placental abruption and your baby is not in distress, you may not have to stay in the hospital.
- You and your baby will be checked often throughout the rest of your pregnancy.
- If you are in preterm labor and are far from your due date, you may be given medicine to stop labor.
If you have moderate to severe placental abruption, you will probably have to stay in the hospital so your baby's health can be watched closely.
- In most cases, the baby will need to be delivered quickly. This means you are likely to have a C-section (cesarean delivery).
- If you have lost a lot of blood, you may need a blood transfusion.
If your baby is premature, he or she may be treated in a neonatal intensive care unit, or NICU. The NICU is geared to the needs of premature or ill newborns.
Can you prevent it?
There is no sure way to prevent placental abruption, but you can do things to lower your risk. Your risk is much higher than normal if you have had placental abruption before, so these steps are very important.
- If you have high blood pressure, follow your doctor's treatment advice.
- Don't smoke while you're pregnant.
- Don't use illegal drugs, like cocaine and meth.
- Get regular prenatal checkups throughout your pregnancy.
Current as of: February 23, 2022
Author: Healthwise Staff
Sarah Marshall MD - Family Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine