Sonography in first trimester bleeding

Vaginal bleeding is the most common cause of presentation to the emergency department in the first trimester. Approximately half of patients with first trimester vaginal bleeding will lose the pregnancy. Clinical assessment is difficult, and sonography is necessary to determine if a normal fetus is present and alive and to exclude other causes of bleeding (eg, ectopic or molar pregnancy). Diagnosis of a normal intrauterine pregnancy not only helps the physician in terms of management but also gives psychologic relief to the patient. Improved ultrasound technology and high-frequency endovaginal transducers have enabled early diagnosis of abnormal and ectopic pregnancies, decreasing maternal morbidity and mortality. The main differential considerations of first trimester bleeding are spontaneous abortion, ectopic pregnancy, or gestational trophoblastic disease. This article reviews the causes of first trimester bleeding and the sonographic findings, including normal features of first trimester pregnancy.