Placental abruption often happens very suddenly. It can cause pain and heavy bleeding and can also deprive the baby of oxygen and nutrients. It can result in serious complications for the mother including bleeding, shock and kidney problems, and threaten the life of the baby.

Although placental abruption can happen from 20 weeks into pregnancy, almost half of them occur after 37 weeks when the mother is closer to full term. In Australia, it affects about 1 in every 100 to 200 pregnancies.

What causes placental abruption?

The causes of placental abruption aren’t known and it is usually nothing that the mother has done to cause it. Serious injury to the abdomen, such as a fall or car accident is thought to be one cause, but often the reason is unknown.

Some some risk factors that may slightly influence the chance of your having a placental abruption, including if:

• you have previously had a placental abruption
• your waters break long before baby is due
• you are having twins or a multiple pregnancy
• you are a smoker or use drugs
• you have high blood pressure or pre-eclampsia
• you have an infection in your uterus
• you are over 35 years old

What are the symptoms of placental abruption?

Placental abruption can cause bleeding during the second half of pregnancy. The amount of bleeding varies from woman to woman. But it doesn’t necessarily indicate how severe the abruption is because sometimes the blood might be trapped behind the placenta and not actually come out of the vagina.

The other main symptom is severe abdominal pain and tends to be a constant pain, rather than coming in waves like contractions. Some women may have no bleeding, but sudden, severe abdominal pain.

How is placental abruption treated?

If your placenta comes away from the uterus, your baby may be at risk because of the lack of oxygen. There is also a risk that you have bleeding inside your uterus. In either case, this is an emergency and you will need to go to hospital.

If only a small part of the placenta has come away, treatment might involve monitoring you and your baby. You may need to stay in bed. In more serious cases, the baby may need to be delivered, usually by caesarean.

If you have any vaginal bleeding during the second or third trimester, it’s important to see your doctor as soon as possible. If the bleeding is severe or you have significant constant pain, call triple zero (000) for an ambulance or go to your nearest hospital emergency department.