ABSTRACT
First trimester bleeding occurs in over 20% of pregnancies. First trimester hemorrhage makes up only a small portion of cases of first trimester bleeding, although the exact incidence of early true hemorrhage is unknown. Significant obstetric bleeding after the first trimester and prior to labor is less common, but is usually clinically significant. History, physical examination, laboratory studies, and ultrasound aid in making the diagnosis. The differential diagnosis for antepartum hemorrhage regardless of trimester includes a heterogeneous group of etiologies. In the first trimester, the gestational age is best established by a crown rump length measurement. Later in pregnancy, a transcerebellar diameter is the best single measurement to assess the gestational age. The severity and etiology of the hemorrhage, along with the gestational age, are the primary determinants of management. The primary initial goal is always the stabilization of the mother, followed by assessment of the fetus for possible delivery.
