Fertility rates among very young adolescent women: temporal and spatial trends in Brazil

BACKGROUND: We assessed whether the reported decrease in fertility rates among 15 to 19 years old Brazilian adolescents has met with a parallel decrease in very young adolescent (10 to 14 years old) fertility rates. So we explored temporal trends for fertility rates among very young adolescents between 2000 and 2012 for Brazil as a whole, its regions and states; and also analyzed the spatial distribution of fertility rates among Brazilian municipalities in the years 2000 and 2012. METHODS: We used data from the Information System on Live Births to calculate the rates. To examine the temporal trends, we used linear regression for time series with Prais-Winsten estimation, including the annual percentage change, for the country, regions, and states. To analyze the spatial distribution among Brazilian municipalities, we calculated the Global Moran Index and created a local Moran significance and cluster map through Local Indicators of Spatial Association (LISA). We also elaborated a thematic map with the rates using empirical Bayesian estimation. RESULTS: Brazilian very young adolescent fertility rates remained high and stable throughout the 2000 to 2012 period, and significantly decreased in three out of 26 states, and in the federal district. On the other hand, an increase was observed in two Northern and Northeastern states. The rates were spatially dependent in Brazilian municipalities (Moran Index = 0.22 in 2012; p = 0.05). The maps indicated a heterogeneous distribution of the rates, with high-rate clusters predominant in the North and low-rate clusters predominant in the South, Southeast, and Midwest. CONCLUSIONS: Our findings indicate that Brazilian very young adolescent fertility rates have not decreased in parallel with adolescent fertility rates as they remain high and did not decrease from 2000 and 2012, even though a few states presented a decrease. Thus, these phenomena probably have distinct underlying causes that warrant further elucidation. Progress in this field is crucial for the development of specific policies and programs focused on very young adolescents.