Overview of common obstetric bleeding disorders.

Most bleeding occurring early in pregnancy is benign; occasionally, however, it can represent an abnormally developing fetus. Vaginal spotting occurs in about 25% of early pregnancies. Other common causes of bleeding during the first trimester of pregnancy are spontaneous abortion, ectopic pregnancy, and gestational trophoblastic disease. Second-trimester bleeding is usually related to an incompetent cervix. Third-trimester bleeding is most likely a sign of placental abnormalities. Most cases of bleeding after the first trimester need prompt referral. This article provides information to help clinicians diagnose, assess, and manage obstetric bleeding. Accurate diagnosis and prompt intervention are crucial in reducing the impact on maternal and perinatal morbidity and mortality.