Ablatio placentae

Definition

Placenta abruptio is separation of the placenta (the organ that nourishes the fetus) from the site of uterine implantation before delivery of the fetus.

Alternative Names

Causes

It is frequently difficult to determine the exact causes of placenta abruptio. Direct causes that result in placenta abruptio are quite rare, but include injury to the abdomen from an auto accident or fall, sudden loss in uterine volume (can occur with rapid loss of amniotic fluid or the delivery of a first twin), or an abnormally short umbilical cord.

Risk factors include:

• A placenta abruptio in a previous pregnancy. After one prior episode there is a 10 - 17% recurrence; after two previous episodes the chance of recurrence exceeds 20%.
• High blood pressure during pregnancy. Approximately 50% of placenta abruptio cases severe enough to cause fetal death are associated with high blood pressure.
• Increased maternal age
• Large number of prior deliveries
• Increased uterine distention (as may occur with multiple pregnancies or abnormally large volume of amniotic fluid)
• Diabetes
• Cigarette smoking
• Cocaine use
• Drinking more than 14 alcoholic drinks per week during pregnancy.

The incidence of placenta abruptio, including any amount of placental separation prior to delivery, is about 1 out of 150 deliveries. The severe form, which results in fetal death, occurs only in about 1 out of 500 to 750 deliveries.

Symptoms

• Vaginal bleeding
• Abdominal pain
• Back pain

Exams and Tests

Tests may include:

• Pelvic exam
• CBC, may note decreased hematocrit or hemoglobin and platelets
• Prothrombin time test
• Partial thromboplastin time test
• Fibrinogen level test
• Abdominal ultrasound

Treatment

Treatment may include IV (intravenous) fluid replacement and blood transfusion. The mother will be carefully monitored for symptoms of shock and signs of fetal distress, which include abnormal heart rates.

An emergency cesarean section may be necessary. If the fetus is very immature and there is only a small separation, the mother may be kept in the hospital for close observation and released after several days the condition does not get worse

If the fetus is mature, vaginal delivery may be chosen if there is minimal distress to the mother and child. Otherwise, a cesarean section may be the preferred choice.

Outlook (Prognosis)

The mother does not usually die from this condition. Maternal death rates in various parts of the world range from 0.5-5%. Early diagnosis of the condition and adequate treatment should decrease the maternal death rate even further. Fetal death rates range from 20-35%. Upon hospital admission, no fetal heart tone is detectable in about 15% of cases.

Fetal distress appears early in the condition in approximately 50% of cases. The infants who live have a 40-50% chance of complications, which range from mild to severe. Concealed vaginal bleeding in pregnancy, excessive loss of blood resulting in shock, absence of labor, a closed cervix, and delayed diagnosis and treatment may increase the risk of maternal or fetal death.

Possible Complications

Excessive loss of blood may lead to shock and possible fetal and/or maternal death. If the site of placental attachment starts to hemorrhage after the delivery and loss of blood cannot be controlled by other means, a hysterectomy (removal of the uterus) may become necessary.

When to Contact a Medical Professional

See your health care provider immediately, call the local emergency number (such as 911), or get to the emergency room if you are pregnant and symptoms of placenta abruptio develop. This may rapidly become an emergency condition that threatens both the mother and the baby.

Prevention

Avoid drinking, smoking, or using recreational drugs during pregnancy. Get early and continuous prenatal care.

Early recognition and proper management of conditions in the mother such as diabetes and high blood pressure also decrease the risk of placenta abruptio.