Sixty-seven pregnancies in practicing physicians were compared with 201 pregnancies in nonphysicians in a historical cohort study. All subjects were cared for and delivered by the same obstetricians. Physician and nonphysician pregnancies of similar socioeconomic status were matched for age, race and parity. After statistically controlling for alcohol and tobacco use and adequacy of prenatal care, physicians had a 1.86 (1.00, 3.46) relative risk of an adverse pregnancy outcome. Physicians were at a 4.0 (1.58, 10.1) and 2.33 (0.93, 5.8) times higher risk for preterm labor and delivery than were nonphysicians. Pregnancies in physicians were found to be similar to those in nonphysicians in the use of obstetric technology except for an increased number of ultrasound examinations among physicians. These results suggest that physicians are at increased risk for an adverse pregnancy outcome and should be considered and treated as a high-risk obstetric group.