The differential diagnosis of hemorrhage in the first postpartum day includes uterine atony (most common), uterine rupture, laceration of the lower genital tract, retained placental tissue, uterine inversion, and coagulopathy. After the first 24 hours, retained products of conception, uterine polyps, or coagulopathy such as von Willebrand disease are more likely causes. An enlarged and “doughy” uterus suggests uterine atony; a vaginal mass suggests an inverted uterus. Bleeding despite good uterine tone and size may indicate retained products of conception or uterine rupture. The vagina and cervix must be inspected for lacerations. The first priority of ED management is stabilization of the patient with crystalloid IV fluids and/or leukoreduced packed red blood cells, if needed. CBC, clotting studies, and type and crossmatching must be obtained. Uterine atony is treated with uterine massage and oxytocin 20 units/L NS at 200 mL/h. Minor lacerations may be repaired in the ED. Extensive lacerations, retained products of conception, uterine inversion, or uterine rupture require emergency operative treatment by the obstetrician.