Association between food environments and fetal growth in pregnant Brazilian women

Birth weight is described as one of the main determinants of newborns' chances of survival. Among the associated causes, or risk factors, the mother's nutritional status strongly influences fetal growth and birth weight outcomes of the concept. This study evaluates the association between food deserts, small for gestational age (SGA), large for gestational age (LGA) and low birth weight (LBW) newborns.

This is a cross-sectional population study, resulting from individual data from the Live Birth Information System (SINASC), and commune data from mapping food deserts (CAISAN) in Brazil. The newborn's size was defined as follows: appropriate for gestational age (between 10 and 90^th percentile), SGA (< 10^th percentile), LGA (> 90^th percentile), and low birth weight < 2,500 g. To characterize food environments, we used tertiles of the density of establishments which sell in natura and ultra-processed foods. Logistic regression modeling was conducted to investigate the associations of interest.

We analyzed 2,632,314 live births in Brazil in 2016, after appropriate adjustments, women living in municipalities with limited availability of fresh foods had a higher chance of having newborns with SGA [OR2nd tertile: 1.06 (1.05-1.07)] and LBW [OR2nd tertile: 1.11 (1.09-1.12)]. Conversely, municipalities with greater availability of ultra-processed foods had a higher chance of having newborns with SGA [OR3rd tertile: 1.04 (1.02-1.06)] and LBW [OR2nd tertile: 1.13 (1.11-1.16)]. Stratification by race showed that Black and Mixed/Brown women had a higher chance of having newborns with SGA [OR3rd tertile: 1.09 (1.01-1.18)] and [OR3rd tertile: 1.06 (1.04-1.09)], respectively, while Mixed-race women also had a higher chance of having newborns with LBW [OR3rd tertile: 1.17 (1.14-1.20)]. Indigenous women were associated with LGA [OR3rd tertile: 1.20 (1.01-1.45)].

The study found that living in areas with limited access to healthy foods was associated with an increased risk of SGA and low birth weight among newborns, particularly among Black and Mixed/Brown women. Therefore, urgent initiatives aimed at reducing social inequalities and mitigating the impact of poor food environments are needed in Brazil.