title: Fertility rates among very young adolescent women: temporal and spatial trends in Brazil.
abstract: 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.
authors.affiliation: School of Nursing, University of São Paulo, Av. Dr. Enéas Carvalho de Aguiar 419, Cerqueira César, CEP 05403-000, São Paulo, SP, Brazil. alvilela@usp.br.
authors.forename: Ana Luiza Vilela
authors.initials: AL
authors.lastname: Borges
authors.affiliation: School of Nursing, University of São Paulo, Av. Dr. Enéas Carvalho de Aguiar 419, Cerqueira César, CEP 05403-000, São Paulo, SP, Brazil.
authors.forename: Christiane Borges do Nascimento
authors.initials: CB
authors.lastname: Chofakian
authors.affiliation: Department of Epidemiology, Faculty of Public Health, University of São Paulo, São Paulo, Brazil.
authors.forename: Ana Paula Sayuri
authors.initials: AP
authors.lastname: Sato
authors.affiliation: School of Nursing, University of São Paulo, Av. Dr. Enéas Carvalho de Aguiar 419, Cerqueira César, CEP 05403-000, São Paulo, SP, Brazil.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Fujimori
authors.affiliation: School of Nursing, University of São Paulo, Av. Dr. Enéas Carvalho de Aguiar 419, Cerqueira César, CEP 05403-000, São Paulo, SP, Brazil.
authors.forename: Luciane Simões
authors.initials: LS
authors.lastname: Duarte
authors.affiliation: CDA-Agricultural Defense Coordination, São Paulo, Brazil.
authors.forename: Murilo Novaes
authors.initials: MN
authors.lastname: Gomes
mesh_terms: D000293:Adolescent; D001723:Birth Rate / Q000639:trends*; D001938:Brazil / Q000453:epidemiology; D002648:Child; D005260:Female; D006801:Humans; D016014:Linear Models; D011247:Pregnancy; D011253:Pregnancy in Adolescence / Q000706:statistics & numerical data*; D062211:Spatio-Temporal Analysis
keywords: Adolescent; Adolescent pregnancy; Age-specific fertility rate; Birth rate; Sexual and reproductive health; Very young adolescent