Overview, Causes, & Risk Factors

Placenta abruptio during pregnancy is a condition in which the placenta, also known as the afterbirth, separates from the womb before the fetus is born. The placenta is a disc-shaped organ that provides nourishment and blood to a fetus. This most common form of this condition occurs in about 1 out of 150 deliveries. The severe form occurs in only 1 out of 500 to 750 births.

What is going on in the body?

In the normal birthing process, the placenta does not detach from the womb until after the infant is born. In placenta abruptio, blood vessels rupture and create a mass of blood, also called a hematoma. This hematoma shears off the blood vessels next to it, creating further bleeding and separation of the placenta.

There are two kinds of placenta abruptio, relating to where the bleeding occurs:

Concealed. This form means that bleeding occurs within the uterus and does not leave the cervix.

External. In this form, blood drains through the cervix and out of the body.

What are the causes and risks of the condition?

It may not be easy to tell what caused placenta abruptio. In fact, doctors can detect an exact cause in less than 5 out of 100 cases. Some causes (though rare) can include:

abdominal trauma from an automobile accident or a fall

sudden loss in size of the uterus, due to loss of amniotic fluid, or delivery of a first twin

abnormally short umbilical cord

However, a woman is more at risk for this condition if she:

has had this condition before

has preeclampsia, which is a condition that develops during pregnancy as a result of hypertension

has eclampsia, which is toxemia during pregnancy that becomes severe

has chronic high blood pressure

is older

has uterine distension from multiple pregnancies, or an excess of amniotic fluid

has had more than four children

has diabetes

has other medical conditions, such as systemic lupus erythematosus

smokes cigarettes

has more than 14 alcoholic drinks per week

uses cocaine

has a history of an attempted internal version, a procedure in which the obstetrician tries changing the baby's position from breech to head first

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Symptoms & Signs

What are the signs and symptoms of the condition?

Symptoms may vary, depending on:

how much of the placenta has detached

during which stage of pregnancy it occurs

Thirty percent of placenta abruptios are small and produce no symptoms. When the case is severe, symptoms may include:

vaginal bleeding

severe abdominal pain, which is different from uterine contractions

uterus is tender and contracted tightly

fetal distress, detected by fetal monitoring

constant contractions, called uterine tetany

back pain

uterine tenderness

maternal shock, with low blood pressure and inadequate blood flow to vital organs

This condition is sometimes confused with placenta previa.

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Diagnosis & Tests

How is the condition diagnosed?

A woman's doctor will look at her medical history and consider any symptoms. He or she also will look for any signs of fetal distress and for tenderness or increased tightness over the uterus. Based on this information, the provider may suspect placenta abruptio.

The diagnosis can be confirmed if:

a pregnancy ultrasound shows a clot behind the placenta

a complete blood count, called CBC, shows decreased hemoglobin, hematocrit, and platelets

a bleeding tendency is found with clotting tests such as a prothrombin time, or PT

the baby's heart rate or rhythm is abnormal

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Prevention & Expectations

What can be done to prevent the condition?

Women can reduce their risk factors by:

avoiding general pregnancy risk factors, such as cocaine, alcohol, or smoking

treating chronic high blood pressure or other conditions, such as diabetes

Good prenatal care will help to identify pregnancy risk factors and possibly allow for early detection of placenta problems. This will mean that treatment can be started right away.

What are the long-term effects of the condition?

This condition can result in:

the death of the mother

the death of the fetus

excessive bleeding leading to shock

a serious generalized bleeding problem called disseminated intravascular coagulopathy, or DIC

kidney failure, also known as renal failure

a liver disease called transfusion hepatitis

low muscle tone, called uterine atony, with continued bleeding

premature delivery, birth trauma, and risks associated with prematurity

However, these results are rare. Maternal death occurs in less than 5 out of 100 women who have placenta abruptio. Fetal death rates are higher. The infant may die in as many as 20 to 35 percent of cases.

What are the risks to others?

This condition can be harmful to the fetus. The woman also has a higher risk of developing this condition during future pregnancies.

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Treatment & Monitoring

What are the treatments for the condition?

This condition is usually an emergency and requires treatment right away. Measures will be taken to keep the mother and infant healthy. This might include:

immediate and continuous internal fetal monitoring of the infant

IV fluids

monitoring of vital signs, such as blood pressure, heart rate, and urine output

"watchful management" if the fetus is not in distress, the mother's vital signs are stable, and labor is not in motion. Some small abruptios will stop bleeding on their own.

vaginal delivery if the infant and mother are stable

cesarean section if the mother and infant are unstable

blood transfusion if signs of shock are present

What are the side effects of the treatments?

Because the treatments for this condition may be life-saving, the potential side effects should be weighed against the loss of life. It may take longer for a woman to recover from major abdominal surgery involved in a cesarean section. Risks for any surgery include bleeding, infection, and allergic reaction to the anesthesia.

What happens after treatment for the condition?

After delivery, the woman will be watched closely for signs of continued bleeding. This entails monitoring frequent CBCs, evaluating clotting times, and watching vital signs. The surviving infant will likewise be observed in the intensive care unit.

How is the condition monitored?

If a woman is pregnant and develops any of the signs of this condition, she should call her doctor right away.

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