INTRODUCTION:
Adolescent pregnancy is an important risk factor for adverse maternal and neonatal outcomes. Most analyses focus on the 15–19 age group, limiting evidence on younger adolescents.

METHODS:
We analyzed trends in adolescent fertility rates (AFR) in Brazil using data from the Live Birth Information System and from the 2000, 2010, and 2022 Demographic Censuses. AFRs were calculated as the ratio of live births to adolescent mothers to the estimated population in the same age group, year, and region, expressed as births per 1,000 adolescents. Estimates were produced for the age groups 10–14, 15–19, and 10–19 years and by macroregion of residence (North, Northeast, South, Southeast, and Central-West). Linear regression models were used to estimate the average annual change (AAC).

RESULTS:
Nationally, AFR declined between 2000 and 2022 from 3.3 to 2.0 births per 1,000 girls aged 10–14 years, from 81 to 40 among those aged 15–19 years, and from 42 to 21 among those aged 10–19 years. Among the youngest, the Northeast had the highest rates, despite a reduction from 9.5 to 5.5 births per thousand (AAC=−0.018 births/year), while the lowest rates were observed in the South and Central-West. The North had the highest AFRs and the largest average reductions, decreasing from 112 to 66 among girls aged 15–19 years (AAC=−2.07) and from 57 to 36 among those aged 10–19 years (AAC=−0.97). In the Northeast, South, and Southeast, average annual declines were −1.80 (15–19 years) and −0.8 (10–19 years).

CONCLUSIONS:
Adolescent fertility in Brazil has declined substantially since 2000, although marked regional inequalities persist. Regions with the highest AFR also experienced the largest reductions over time. These findings highlight important progress alongside persistent interregional disparities and reinforce the need for region-specific policies and strategies to further reduce adolescent fertility and promote health equity.