The Association Between Maternal Work Precarity and Infant Low Birth Weight in a Nationally Representative Cohort of Women in the United States

As a larger proportion of women enter and remain in the workforce, consideration should be given to how work characteristics can affect pregnancy outcomes. We investigated the association between maternal work precarity and delivery of a low birth weight infant. Data on work characteristics and covariates were collected from 2,871 women enrolled in the National Longitudinal Survey of Youth 1979 and outcome information was obtained from the National Longitudinal Survey of Youth Children Cohort. Work precarity was characterized as a composite measure of four work characteristics (material rewards [score 0-2], working time arrangements [score 0-2], collective organization [score 0-1], and employability opportunities [score 0-1]) and was categorized into three groups labeled low (0-2), medium (3), and high (4-6) based on the number of characteristics that a participant had. Low birth weight was defined as weight less than 2500 grams at birth. Logistic regression models were fit to calculate odds ratios and 95% confidence intervals adjusted for maternal age, race/ethnicity, educational attainment, pre-pregnancy body mass index, infant year of birth, alcohol consumption, and smoking during pregnancy. We also assessed effect modification by maternal race/ethnicity and infant sex using stratified analyses. Women with high work precarity tended to have less than a high school education and to smoke. They were also less likely to consume alcohol. Women with medium (OR:1.40, 95%CI: 1.00-1.96) and high (OR: 1.57, 95%CI: 1.13-2.16) work precarity were more likely to have a low birth weight delivery compared to women with low work precarity. The association between medium work precarity and low birth weight was significant among Non-Hispanic Black women (OR: 2.10; 95%CI: 1.05-4.21) but was not significant among Non-Hispanic White women (OR: 1.40; 95%CI: 0.90-2.17) or Hispanic women (OR: 0.96; 95%CI: 0.41-2.24). High work precarity was associated with low birth weight among female infants (OR:1.78; 95%CI: 1.14-2.76) but not among male infants (OR:1.35; 95%CI: 0.83-2.18). Findings of this study can be used to better inform antenatal care and identify women with potential adverse pregnancy outcomes.