PURPOSE: To determine social and behavioral consequences of pregnancy and how these differed according to the pregnancy outcome (live birth or abortion) 1 year after the event. METHODS: This was a prospective study of two groups of young women aged 12-18 years, one attending prenatal services and the other admitted for abortion complications at the same hospital in northeast Brazil. Adolescents who gave birth were subsequently classified as having intended or unintended pregnancies, and those who aborted were divided between those who terminated their pregnancies and those who miscarried. Baseline data were collected between 1995 and 1997 from all teens who met the eligibility criteria. Information was collected through one-on-one interviews using a questionnaire that was structured and precoded. Multiple logistic regression was used to identify characteristics that predicted outcomes at 1 year. RESULTS: Teens who terminated their pregnancies were the most likely to be in school or working 1 year later. They also showed the greatest increase in self-esteem. The young mothers, however, had the highest self-esteem but perceived the impact of pregnancy on their lives as being more negative than they did initially. Group affiliation was not associated with the quality of partner relationships, which tended to deteriorate over time. The young mothers used contraception at 1 year at higher rates and had experienced fewer subsequent pregnancies than the two abortion groups. CONCLUSIONS: The experience of adolescent pregnancy for this group of teens produced mixed findings, some more negative than others. Interventions to decrease the adolescent's desire to have a baby will have to be tailored differently from those designed to prevent an unintended pregnancy, but both are needed.