Emergencies in early pregnancy.

First-trimester vaginal bleeding and abdominal pain are common complaints in the emergency department. The differential diagnosis is broad, ranging from benign conditions to life-threatening complications. This is a difficult topic because it is charged not only with immediate emotional connotations but also with potential long-term effects on the patient's ability to become pregnant again. This article reviews the presentation, diagnosis, and management of implantation bleeding, subchorionic hemorrhage, spontaneous abortion, ectopic pregnancy, heterotopic pregnancy, anembryonic pregnancy, hyperemesis gravidarum, gestational trophoblastic disease, and round ligament syndrome.