This retrospective cohort study evaluated the risk of adverse pregnancy outcomes following motor vehicle crashes during pregnancy. The authors assessed outcomes of pregnant women hospitalized for motor vehicle crashes in Washington State from 1989 to 2001 (n = 582). They used the Injury Severity Score (ISS) to classify 84 severely injured (ISS > or =9), 309 non-severely injured (ISS 1-8), and 189 uninjured (ISS 0) pregnant women and compared them with pregnant women who had not been hospitalized for a motor vehicle crash (n = 17,274). Of pregnant women in motor vehicle crashes, 82.9% were hospitalized and discharged without delivering, and 17.1% delivered at hospitalization. Compared with women not in motor vehicle crashes, severely and non-severely injured women were at increased risk of placental abruption and cesarean delivery, and their infants were at increased risk of respiratory distress syndrome and fetal death. Uninjured women were also at increased risk of preterm labor (relative risk = 7.9, 95% confidence interval: 6.4, 9.8) and placental abruption (relative risk = 6.6, 95% confidence interval: 3.9, 11.2) compared with women not in motor vehicle crashes. Pregnant women hospitalized following motor vehicle crashes are at increased risk of adverse pregnancy outcomes, regardless of the presence or severity of injuries.