In utero exposure to economic fluctuations and birth outcomes: An analysis of the relevance of the local unemployment rate in Brazilian state capitals

Objective Analyze if in utero exposure to economic downturns is associated with worsened birth outcomes. Methods We used birth records from all live singleton births in the 27 Brazilian state capitals between October 2012 and December 2016 (n = 2,952,430) and linked them to local unemployment rates according to the mother's residence. We estimated the association between different birth outcomes and the local unemployment rate in the three trimesters before birth. We included maternal characteristics and month, year and municipality fixed effects as covariates. We also estimated the association for different groups of mothers, based on marital status, educational level, age and race. Results A 1 p.p. increase in the local unemployment rate in the trimester before birth is associated with 2.68% higher odds of being born with very low birthweight (< 1500 grams) (OR: 1.0268, 95% CI: 1.0006-1.0536). That result is pushed by the effect among newborns from mothers younger than 24 (OR: 1.0684, 95%CI: 1.0353-1.1024), from mothers with 11 years of schooling or less (OR: 1.0477, 95% CI: 1.0245-1.0714), and from brown or black mothers (OR: 1.0387, 95%CI: 1.0156-1.0624). The associations among children born from younger, less educated and black or brown mothers are robust to the application of a procedure to control for multiple testing, albeit the results considering the whole sample are not. Conclusions Our study shows that there is an association between in utero exposure to higher unemployment rates during the last gestational trimester and the odds of being born with VLBW among children born from mothers younger than 24 years old, with less of 11 years of education and black or brown. These results suggest that children born from women of low socioeconomic status are more vulnerable to in utero exposure to economic downturns.