Placenta previa or abruptio placentae should always be suspected in women who present with vaginal bleeding in the second half of pregnancy. Placenta previa, a placenta implanted over the cervical os, and abruptio placentae, the premature separation of a normally implanted placenta, are significant causes of maternal morbidity and perinatal morbidity and mortality. The bleeding also may result from a slight marginal separation of the placenta that is transient or from injury to the lower genital tract; occasionally, no source can be identified. It is the responsibility of the physician to determine whether or not the bleeding is potentially life threatening to the pregnant woman or fetus or whether it is benign. In today's era of cost conscious medicine, the physician also must determine, if immediate delivery is not needed, whether the preterm patient should be expectantly managed as an inpatient or an outpatient.