Through the collaboration among University of California at Berkeley School of Public Health, Samuel Merritt College, and a private nonprofit, community-based medical center, the adequacy of two perinatal programs was assessed based on the pregnancy outcomes of teenaged Medi-Cal clients. Historical data from June 1991 to June 1992 were compiled on the pregnancy outcomes of 312 Medi-Cal clients, 12-18 years of age, delivering at the study medical center in Oakland, California. The effect of enrollment in two special perinatal programs, Comprehensive Perinatal Services Program (CPSP) and a school-based program, the Comprehensive Teenage Pregnancy and Parenting Program (CTAPPP), on the occurrence of adverse perinatal outcomes was examined. Adverse perinatal outcomes were defined as the occurrence of one of the following: low birthweight (< 2,500 grams), gestational age less than 37 weeks, or admission to the neonatal intensive care unit (NICU), not related to congenital syphilis. The percentage of teens experiencing adverse perinatal outcomes was 10.9% at the study hospital. No significant association was observed between CTAPPP enrollment and reduced adverse perinatal outcomes, but CPSP enrollment was associated with reduced adverse perinatal outcomes. This association persisted after controlling for potential confounders, including substandard prenatal care, which were also found to be risk factors for adverse perinatal outcomes. Enrollment in both programs simultaneously was not associated with a reduction in adverse outcomes. The significant association between CPSP enrollment and reduced adverse perinatal outcomes indicates that a more comprehensive prenatal program may be beneficial in improving birth outcomes, specifically among high-risk teenage populations.(ABSTRACT TRUNCATED AT 250 WORDS)