Abruptio Placentae

Abruptio placentae - also called placental abruption­occurs when the placenta separates from the uterine wall prematurely, usually after the 20th week of gestation, producing hemorrhage. This disorder may be classified according to the degree of placental separation and the severity of maternal and fetal symptoms.

Abruptio placentae is most common in multigravidas - usually in women over age 35 - and is a common cause of bleeding during the second half of pregnancy. A firm diagnosis when there is heavy maternal bleeding generally necessitates termination of the pregnancy. The fetal prognosis depends on the gestational age and amount of blood lost. The maternal prognosis is good if hemorrhage can be controlled.

Causes

The exact cause is not known; but high blood pressure, heart disease, and arthritis make it more likely. A trauma such as a car accident or a fall may trigger the problem. Cocaine abuse increases the risk.

Signs and Symptoms

Abruptio placentae produces a wide range of clinical effects, depending on the extent of placental separation and the amount of blood lost from maternal circulation.

A patient with mild abruptio placentae (marginal separation) may report mild to moderate vaginal bleeding, vague lower abdominal discomfort, and mild to moderate abdominal tenderness. Fetal monitoring may indicate uterine irritability. Auscultation reveals strong and regular fetal heart tones.

A patient with moderate abruptio placentae (about 50% placental separation) may report continuous abdominal pain and moderate dark red vaginal bleeding. Onset of symptoms may be gradual or abrupt.

Vital signs may indicate impending shock. Palpation reveals a tender uterus that remains firm between contractions. Fetal monitoring may reveal barely audible or irregular and bradycardic fetal heart tons. Labor usually starts within 2 hours and often proceeds rapidly.

A patient with severe abruptio placentae (70% placental separation) will report abrupt onset of agonizing, unremitting uterine pain (described as tearing or knifelike) and moderate vaginal bleeding.

Vital signs indicate rapidly progressive shock. Fetal monitoring indicates an absence of fetal heart tones.

Palpation reveals a tender uterus with boardlike rigidity. Uterine size may increase in severe concealed abruptions.

Assessment Tip Draw a line at the level of the fundus and check it every 30 minutes. If the level of the fundus increases, suspect abruptio placentae.

Diagnostic tests

Pelvic examination under double setup (preparations for an emergency cesarean) and ultrasonography are performed to rule out placenta previa. Decreased hemoglobin levels and platelet counts support the diagnosis. Periodic assays for fibrin split products aid in monitoring the progression of abruptio placentae and in detecting DIC. Differential diagnosis excludes placenta previa, ovarian cysts, appendicitis, and degeneration of leiomyomas.

Treatment

Medical management of abruptio placentae is intended to assess, control, and restore the amount of blood lost; to deliver a viable infant; and to prevent coagulation disorders.

Immediate measures for abruptio placentae include starting an I. V. infusion (by large-bore catheter) of appropriate fluids (lactated Ringer's solution) to combat hypovolemia, inserting a central venous pressure line and an indwelling urinary catheter to monitor fluid status, drawing blood for hemoglobin and hematocrit determination and coagulation studies and for typing and cross matching, starting external electronic fetal monitoring, and monitoring maternal vital signs and vaginal bleeding.

After determining the severity of placental abruption and appropriate fluid and blood replacement, prompt delivery by cesarean section is necessary if the fetus is in distress. If the fetus isn't in distress, monitoring continues; delivery is usually performed at the first sign of fetal distress. (If placental separation is severe with no signs of fetal life, vaginal delivery may be performed unless uncontrolled hemorrhage or other complications contraindicate it.)

Because of possible fetal blood loss through the placenta, a pediatric team should be ready at delivery to assess and treat the neonate for shock, blood loss, and hypoxia.

Complications of abruptio placentae require appropriate treatment. With a complication, such as DIC, for example, the patient needs immediate intervention with heparin, platelets, and whole blood, as ordered, to prevent exsanguination.

Prevention

Avoid drinking, smoking or using other 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.