objective: to determine frequency and maternal-perinatal consequences of the adolescent pregnancy in 23 hospitals of the ministry of health of peru. methods: case-control study who compared maternal and perinatal risk between pregnant teenagers (10 to 19 years) and pregnant adults (20 to 29 years). variables were obtained and analyzed from the perinatal data system. for the analysis, were used frequencies and odds ratio with 95% of confidence interval. results: adolescents represent 19.2% of births, with significant differences between natural regions (17.6% highland, 18.1% coast and 29% jungle). low education, high economic dependence, unstable marital status, jungle region and poor nutritional status, were associated with adolescent pregnancies. the negative maternal effects were: inadequate (or=1.2) and late prenatal care (or=1.56), morbidity (or=1.18), anemia (or=1.24), urinary tract infection (or=1.3), hypertensive disease of pregnancy (or=1.3) and puerperal infection (or=1.44). the negative perinatal effects were: low birth weight (or=1.36), prematurity (or=1.29), fetal malnutrition (or=1.34), depression at 1 minute of live (or=1.17), neonatal morbidity (or=1.1), birth trauma (or=1.36) and neonatal mortality (or=1.49). conclusion: the adolescents pregnant have unfavorable sociodemographic conditions, poor nutrition, high risk of maternal and neonatal morbidity and mortality compared with adults pregnant.