Prevalence and factors associated with low birth weight in the state of Minas Gerais, Brazil

Introduction: One of the health indicators of the newborn children is low birth weight (LBW) - weight less than 2,500g - which can be determined by the influence of several reasons, such as, maternal, fetal, placental and environmental factors. Objective: To determine the prevalence and factors associated with LBW in the state of Minas Gerais (MG), Brazil. Method: Cross-sectional study which analyzed data from 259,863 live births, in MG, from Brazilian Live Birth Information System (SINASC), in 2011. Of these, 242,487 records met the inclusion criteria: birth weight equal to or greater than 500g, no malformations, 22 weeks or more of gestational age. The prevalence of the LBW was determined. The crude and adjusted prevalence ratios were determined by Poisson regression. Results: The prevalence of LBW was 9.2%. The prevalence was higher in mothers with lower educational level, primiparity, dead children from previous pregnancies, prenatal care with less than 5 visits to doctor, gestational age less than 37 weeks, multiple pregnancy, and female newborn. The prevalence was lower in the North, Northeast, Northwest, Eastern of South, Southeast, Southern Triangle, East and Jequitinhonha health macro-regions. Conclusion: The LBW prevalence was high, and the variables associated with higher LBW prevalence were gestational age, multiple pregnancy, educational level, number of prenatal visits to doctor, parity, gender, place of birth. The lower prevalence was observed in the health macro-regions in which the socioeconomic and sanitary conditions are worst, characterizing the LBW paradox.