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The most worrisome causes of bleeding in late pregnancy are placenta previa (see Abnormalities of Pregnancy: Placenta Previa) and abruptio placentae (see Abnormalities of Pregnancy: Abruptio Placentae); either can result in hemorrhagic shock, which should be treated with IV fluid resuscitation and other measures before or during evaluation. Other obstetric causes include labor (with expulsion of a bloody mucus plug) and occult marginal placental separation. Disseminated intravascular coagulation (DIC) is an uncommon but significant complication of abruptio placentae. Because pelvic blood flow increases during late pregnancy, previously asymptomatic cervical and vaginal lesions (eg, polyps, ulcers) that are unrelated to pregnancy often bleed for the 1st time.
Evaluation
History:
Risk factors for abruptio placentae include prior abruptio placentae, maternal age > 35, multiparity, hypertension, tobacco use, substance abuse (particularly of cocaine), abdominal trauma, maternal sickle cell anemia, thrombotic disorders, vasculitis, and other vascular disorders. Risk factors for placenta previa include multiparity, multifetal pregnancy, prior uterine surgery (particularly cesarean section), and other uterine abnormalities that can interfere with implantation (eg, fibroids). Placenta previa is usually recognized and diagnosed prenatally during routine ultrasonography (see Abnormalities of Pregnancy: Symptoms, Signs, and Diagnosis).
Dark, small-volume vaginal bleeding with moderate to severe uterine pain suggests abruptio placentae. Bright, large-volume vaginal bleeding with mild or minimal uterine pain suggests placenta previa.
Examination:
Digital examination of the cervix should not be done until placenta previa has been excluded. Such examination can precipitate torrential bleeding in women with placenta previa. Speculum examination can be done but must be done very carefully. However, if placenta previa is present, speculum examination rarely provides any information that would alter clinical management.
Signs of hemorrhagic shock or hypovolemia out of proportion to degree of vaginal bleeding suggest abruptio placentae, as do DIC and uterine irritability and tenderness.
Testing:
If bleeding is minimal, blood typing and Rh testing are done to determine whether Rh0(D) immune globulin is needed (see Abnormalities of Pregnancy: Erythroblastosis Fetalis). If bleeding is significant, CBC, PT, PTT, blood typing, and cross-matching are indicated. If abruptio placentae is suspected, fibrinogen level and fibrin-split products are also measured to check for DIC.
Pelvic ultrasonography or fetal monitoring may be necessary, but testing should not delay obstetric consultation because immediate delivery may be indicated. Fetal distress out of proportion to vaginal bleeding suggests abruptio placentae.
Treatment
Hemorrhagic shock (see Shock and Fluid Resuscitation: Prognosis and Treatment) and DIC (see Coagulation Disorders: Treatment) are treated immediately. If hemorrhagic shock, DIC, abruptio placentae, or placenta previa are present, an obstetrician determines the method and timing of delivery.
Last full review/revision November 2005
Content last modified November 2005
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