First Trimester Bleeding: Evaluation and Management.

Approximately one-fourth of pregnant women will experience bleeding in the first trimester. The differential diagnosis includes threatened abortion, early pregnancy loss, and ectopic pregnancy. Pain and heavy bleeding are associated with an increased risk of early pregnancy loss. Treatment of threatened abortion is expectant management. Bed rest does not improve outcomes, and there is insufficient evidence supporting the use of progestins. Trends in quantitative ß subunit of human chorionic gonadotropin (ß-hCG) levels provide useful information when distinguishing normal from abnormal early pregnancy. The discriminatory level (1,500 to 3,000 mIU per mL) is the ß-hCG level above which an intrauterine pregnancy should be visible on transvaginal ultrasonography. Failure to detect an intrauterine pregnancy, combined with ß-hCG levels higher than the discriminatory level, should raise concern for early pregnancy loss or ectopic pregnancy. Ultrasound findings diagnostic of early pregnancy loss include a mean gestational sac diameter of 25 mm or greater with no embryo and no fetal cardiac activity when the crown-rump length is 7 mm or more. Treatment options for early pregnancy loss include expectant management, medical management with mifepristone and misoprostol, or uterine aspiration. The incidence of ectopic pregnancy is 1% to 2% in the United States and accounts for 6% of all maternal deaths. Established criteria should be used to determine treatment options for ectopic pregnancy, including expectant management, medical management with methotrexate, or surgical intervention.