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Abruptio
placentae is premature separation of a normally implanted placenta
from the uterus during late pregnancy. Manifestations 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 may involve any degree of placental separation, from a few millimeters to complete detachment. It results in bleeding into the decidua basalis behind the placenta (retroplacentally). Cause is unknown. Fetal ischemia can result. It can cause fetal death if it is acute and disrupts the bulk of uteroplacental blood flow; it can cause growth restriction if it is chronic and less extensive.
Risk factors include older maternal age, hypertension (pregnancy-induced or chronic), vasculitis, other vascular disorders, prior abruptio placentae, abdominal trauma, maternal thrombotic disorders, tobacco use, and particularly cocaine use. Abruptio placentae occurs in 0.4 to 1.5% of all pregnancies.
Symptoms and Signs
Abruptio placentae may result in blood exiting through the cervix (external hemorrhage) or remaining behind the placenta (concealed hemorrhage). Severity of symptoms and signs depends on degree of separation and blood loss. The uterus may be painful, tender, and irritable to palpation. Hemorrhagic shock may occur, as may signs of disseminated intravascular coagulation (DIC).
Diagnosis
Diagnosis is suggested by vaginal bleeding, uterine pain and tenderness, fetal distress, hemorrhagic shock, or DIC in late pregnancy, particularly if degree of tenderness or shock appears disproportionate to degree of vaginal bleeding. If bleeding occurs in late pregnancy, placenta previa, which has similar symptoms, must be ruled out before pelvic examination is done; examination may increase bleeding if placenta previa is present. Evaluation includes fetal heart monitoring, CBC, measurement of serum fibrinogen and fibrin-split products, and transabdominal pelvic ultrasonography. Fetal heart monitoring may detect a nonreassuring pattern or fetal death. Ultrasonography is insensitive; thus, diagnosis may ultimately be clinical.
Treatment
If bleeding does not threaten the life of the mother or fetus, if the fetal heart rate pattern is reassuring, and if the pregnancy is not near term, hospitalization and bed rest are advised; they may reduce the bleeding. If bleeding resolves, ambulation and usually hospital discharge are allowed. If bleeding continues, prompt delivery is indicated; method is chosen using criteria similar to that for preeclampsia or eclampsia (see Abnormalities of Pregnancy: Preeclampsia and Eclampsia). Vaginal delivery accelerated by IV oxytocin or delivery by cesarean section is usually indicated, depending on the rapidity of maternal and fetal deterioration. Amniotomy (artificial rupture of membranes) is done early because it may accelerate delivery, preventing DIC. Treatment of complications (eg, shock, DIC) is supportive.
Last full review/revision November 2005
Content last modified November 2005
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