Vaginal bleeding in pregnancy.

The process of identifying and evaluating the common causes of vaginal bleeding during pregnancy changes as the pregnancy progresses to term. The most common identifiable causes of vaginal bleeding during early pregnancy include spontaneous abortion and ectopic pregnancy. Pelvic ultrasound and quantitative beta-human chorionic gonadotropin measurements are used in the evaluation of early-stage bleeding in pregnancy. During the middle and late stages of pregnancy, placental abnormalities become important in the differential diagnosis of vaginal bleeding. Placenta previa classically presents as painless bleeding and is evaluated with ultrasound. Patients with placental abruption may present with abdominal pain and bleeding. As pregnancy progresses to term, bloody show must be considered as a common source of bleeding. Vaginal and cervical lesions can cause vaginal bleeding in any stage of pregnancy.