The obstetric component of The Johns Hopkins Adolescent Pregnancy Program is described and the pregnancy outcome for adolescents delivering btween 1976 and 1981 is compared with that of similar young women who were delivered in the same facilities, by the same staff, but who received their prenatal care in other Hopkins-related programs. The adolescent program is comprehensive, providing intensive psychosocial support and patient education in addition to medical care, using a team approach coordinated by an individual case management system. Enrollees had fewer pregnancy complications and lower perinatal mortality. Between 1979 and 1981, the frequency of birth weight below 2500 g was 9.9%, and below 1500 g, 1.9% for program adolescents, compared with 16.4 and 3.9%, respectively, for controls. Younger adolescents in the program entered prenatal care significantly later than older ones. However, those aged 14 years and below had infants with the highest average birth weight and no greater risk of perinatal death than those of older adolescents.