Abstract Objectives: to compare the adverse perinatal outcomes in pregnancies of adolescents and elderly women of public health network. Methods: a cross-sectional study carried out with pregnant women at the extremes of reproductive age according to the classification of the Brazilian Ministry of Health (adolescents those aged ≤19 years and those who were older than 35 years) and their newborns. Socioeconomic data (income, schooling, occupation and marital status), as well as clinical (diseases), anthropometric (maternal BMI) and perinatal (gender, weight, length, Apgar and gestational age) data were collected, and Poisson regression in hierarchical model was performed, with the results in Ratio of Prevalence (PR) and its respective Confidence Interval at 95% (95% CI). Results: when comparing adolescent and elderly women, 38.7% vs 54.6% (PR=0.71, CI=0.54-0.94, p=0.002) were observed, respectively, cesarean deliveries; 37.8% vs 25.2% (PR=0.83, CI=0.58-1.19, p=0.332) preterm births; 16.6% vs 20.5% (RP=1.07, CI=0.78-1.46, p=0.666) births of small infants for gestational age (SGA); 18.0% vs 15.3% (RP=1.01, CI=0.69-1.47, p=0.948) births of large-for-gestational-age newborns (LGA); 32.2% vs 34.7% (RP=1.08, CI=0.82-1.42, p=0.578), low birth weight infants and 28.5% vs 42.9% (RP=1.18, CI=0.91-1.54, p=0.201) with high birth length. Conclusions: When compared with adolescent women, pregnant women of advanced age presented a higher frequency of cesarean deliveries.