• Merck Manual
• >
• Health Care Professionals
• >
• Gynecology and Obstetrics
• >
• Abnormalities of Pregnancy
4

Abruptio placentae is premature separation of a normally implanted placenta from the uterus after 20 wk gestation. It is an obstetric emergency. Manifestations may include vaginal bleeding, uterine pain and tenderness, hemorrhagic shock, and disseminated intravascular coagulation. Diagnosis is clinical and sometimes by ultrasonography. Treatment is bed rest for mild symptoms and prompt delivery for severe or persistent symptoms.

Abruptio placentae occurs in 0.4 to 1.5% of all pregnancies; incidence peaks at 24 to 26 wk gestation.

Abruptio placentae may involve any degree of placental separation, from a few millimeters to complete detachment. Separation can be acute or chronic. Separation results in bleeding into the decidua basalis behind the placenta (retroplacentally). Cause is unknown.

Risk factors: Risk factors include the following:

• Older maternal age
• Hypertension (pregnancy-induced or chronic)
• Placental ischemia (ischemic placental disease) manifesting as intrauterine growth restriction
• Polyhydramnios
• Intra-amniotic infection (chorioamnionitis)
• Vasculitis
• Other vascular disorders
• Prior abruptio placentae
• Abdominal trauma
• Maternal thrombotic disorders
• Tobacco use
• Premature rupture of membranes
• Cocaine use (risk of up to 10%)

Complications: Complications include the following:

• Maternal blood loss (possibly with shock, disseminated intravascular coagulation [DIC], or both)
• Fetal ischemia (causing fetal distress or death if ischemia is acute or severe growth restriction if ischemia is chronic and mild)
• Sometimes fetomaternal transfusion and Rh sensitization

Symptoms and Signs

Acute abruptio placentae may result in bright red blood exiting through the cervix (external hemorrhage). Blood may also remain behind the placenta (concealed hemorrhage). Severity of symptoms and signs depends on degree of separation and blood loss. As separation continues, the uterus may be painful, tender, and irritable to palpation. Hemorrhagic shock may occur, as may signs of DIC. Chronic abruptio placentae may cause continued or intermittent dark brown spotting.

Abruptio placentae may cause no or minimal symptoms and signs.

Diagnosis

• Combination of clinical, laboratory, and ultrasonographic findings

Diagnosis is suggested if any of the following occur during late pregnancy:

• Vaginal bleeding
• Uterine pain and tenderness
• Fetal distress or death
• Hemorrhagic shock
• DIC
• Tenderness or shock disproportionate to the degree of vaginal bleeding

The diagnosis should also be considered in women who have had abdominal trauma. If bleeding occurs during late pregnancy, placenta previa, which has similar symptoms, must be ruled out before pelvic examination is done; if placenta previa is present, examination may increase bleeding.

Evaluation includes the following:

• Fetal heart monitoring
• CBC
• Blood and Rh typing
• PT/PTT
• Serum fibrinogen and fibrin-split products (the most sensitive indicator)
• Transabdominal or pelvic ultrasonography
• Kleihauer-Betke test if the patient has Rh-negative blood—to calculate the dose of Rh₀(D) immune globulin needed

Fetal heart monitoring may detect a nonreassuring pattern or fetal death.

Transvaginal ultrasonography may be done if transabdominal ultrasonography rules out placenta previa. However, ultrasonography is insensitive; thus, diagnosis may ultimately be clinical.

Treatment

• Usually prompt delivery and aggressive supportive measures
• Trial of hospitalization and bed rest if the pregnancy is not near term and if mother and fetus are stable

Prompt cesarean delivery is usually indicated if any of the following is present:

• Maternal hemodynamic instability
• Nonreassuring fetal heart rate pattern
• Near-term pregnancy

However, oxytocinSome Trade Names
PITOCIN
SYNTOCINON
Click for Drug Monograph
may be given to accelerate vaginal delivery, depending on the stage of labor and the rapidity of maternal and fetal deterioration (eg, oxytocinSome Trade Names
PITOCIN
SYNTOCINON
Click for Drug Monograph
may be given if delivery appears imminent and the mother and fetus are stable). Amniotomy (deliberate rupture of membranes) is done early because it may accelerate delivery, preventing DIC.

Hospitalization and bed rest are advised if all of the following are present:

• Bleeding does not threaten the life of the mother or fetus.
• The fetal heart rate pattern is reassuring.
• The pregnancy is not near term.

This approach ensures that mother and fetus can be closely monitored and, if needed, rapidly treated. Corticosteroids should be considered (to accelerate fetal lung maturity) if gestational age is < 34 wk. If bleeding resolves and maternal and fetal status remains stable, ambulation and usually hospital discharge are allowed. If bleeding continues or if status deteriorates, prompt cesarean delivery is indicated.

Complications (eg, shock, DIC) are managed with aggressive replacement of blood and blood products.

Last full review/revision February 2010 by Antonette T. Dulay, MD

Content last modified February 2010