What Is Placental Abruption?

Placental abruption occurs when the placenta separates from the wall of the uterus prematurely. The placenta is an organ which provides blood flow and oxygen to the fetus. The condition is also called abruptio placenta.

When a placenta separates prematurely, a fetus loses its lifeline. Prematurity and birth-related asphyxia (lack of oxygen) may result in stillbirth. Researchers have noted an increase in infant mortality in babies who survive placental abruption, even beyond the perinatal period (which ends seven days after birth).

In addition, the complication can result in severe maternal hemorrhage. Placental abruption is a life-threatening medical emergency. 

During placental abruption, the placenta may separate entirely or partially. Most often, placental abruption is a complication of the third trimester. But it can also occur earlier in the second half of pregnancy and during labor. Placental abruption occurs in 1% of pregnancies.

Signs / Symptoms of Placental Abruption

When the placenta separates from the uterine wall, blood vessels connecting the placenta to the endometrium (uterine lining) bleed. How much bleeding or how many other symptoms occur depends on how much of the placenta has detached.

Placental abruption may be mild, moderate, or severe. With mild placental abruption, the placenta has only partially detached. There may not be very many symptoms, or symptoms may be slight. 

Moderate to severe placental abruption involves a placenta that is significantly separated or has wholly detached. Severe cases may result in maternal shock, hemorrhage, and fetal death.

The predominant symptom of placental abruption is vaginal bleeding during the third trimester. The bleeding is usually accompanied by pain. 

Signs of abruption are similar to other health conditions. They include:

• Vaginal bleeding
• Pain or tenderness in the abdomen
• Very painful contractions that are close together in timing
• Back pain
• Blood in the bag of waters
• Faintness
• The baby not moving as much as previously

Causes and Risk Factors

In an uncomplicated pregnancy, the placenta detaches from the uterus during the third stage of labor. With placental abruption, the placenta detaches prematurely. This may be either during pregnancy or during the first or second stage of labor.

The exact cause of placental abruption is unknown. However, when a placenta detaches, it does so because something has disrupted the network of blood vessels.

Some factors may raise a person’s risk for placental abruption. Many risk factors are unavoidable, but there are some things that you can do to reduce your risk. Risk factors include:

• Placental abruption in a previous pregnancy
• Long-term high blood pressure
• Preeclampsia (sudden high blood pressure in pregnancy)
• Heart disease
• Trauma to the abdomen
• Smoking
• Alcohol use
• Cocaine use
• Uterine fibroids
• Being over 40
• Pregnancies of multiples (twins, triplets, or more)
• Sudden rupture of the membranes

Diagnosis

Placental abruption is usually diagnosed based on symptoms, especially bleeding and abdominal pain. An ultrasound can determine the location of the placenta. This imaging uses sound waves to visualize the fetus and placenta. But detection by ultrasound is low because bleeding around the placenta can appear similar to the placenta itself.

A definitive diagnosis can only be made after examination of the placenta following birth. A placenta that has abrupted will usually have an area of clotted blood.

Bleeding during the second half of pregnancy can have other causes, like placenta previa. Your healthcare provider needs to differentiate between potential causes to identify the proper course of treatment.

Treatment

It is not possible to re-attach a placenta that has separated from the uterus. Instead, your healthcare provider will identify the severity of the abruption and determine how best to manage your pregnancy or labor.

Mild

If your symptoms are mild and you and your fetus are exhibiting no signs of distress, your practitioner may suggest close monitoring. This type of management may be preferred if your pregnancy is less than 37 weeks.

You will likely be admitted to the hospital so that you have access to life-saving interventions if they become necessary. Your healthcare provider will monitor you and your baby until there is a change in your condition or until it is safe to deliver your baby.

Moderate or Severe

If your symptoms are moderate or severe, the safest course of action is to deliver the baby. Depending on the situation and how precipitous the labor is, your baby may be born vaginally or by Cesarean section (C-section), which is a surgical procedure to deliver the baby.

If your baby is in distress, your healthcare provider will likely perform an emergency C-section. In cases of severe blood loss, you may require a blood transfusion.

Complications

Each year in the United States, more than 1% of maternal deaths are linked to placental abruption. A 2015 study from the Netherlands found a recurrence rate for placental abruption of just under 6%.

Placental abruption is associated with high perinatal mortality and morbidity rates. Prematurity and birth-related asphyxia are the leading causes of these outcomes.

The perinatal fetal/infant mortality rate related to placental abruption is around 10%. The prognosis depends on the severity of the complication.

Complications that can result from placental abruption include:

• Severe hemorrhage (bleeding)
• Fetal death
• Maternal death
• Prematurity
• Coagulopathy (clotting disorder)
• Complications from transfusions
• Hysterectomy (surgical removal of the uterus)
• Complications associated with C-sections
• Increased risk of cardiac events

Summary

Placental abruption is a pregnancy complication in which the placenta detaches from the uterus too soon. This can result in bleeding and lack of oxygen for the fetus, with risks for both the parent and fetus.

It is diagnosed by symptoms, including vaginal bleeding. Placental abruption may be treated with close monitoring or immediate delivery by vaginal birth or C-section.

A Word From Verywell

Placental abruption can be a frightening diagnosis. If you are concerned that you may be experiencing possible symptoms of placental abruption, don’t wait until your next prenatal appointment to mention it. Call your healthcare provider’s office right away, as early intervention can be lifesaving.

Placental abruption is rare, but the recurrence rate is significant. So, if you have had placental abruption in a past pregnancy, be sure your practitioner is aware. 

You can reduce your risk of placental abruption by avoiding things like cigarettes, alcohol, and other substances. If you have existing health conditions, be sure that you are working with your healthcare provider to manage them.