Effects of maternal homelessness, Special Supplemental Nutrition Program for Women, Infants and Children (WIC), and prenatal PM2.5 exposure on birthweight in a multi-ethnic and low-income urban community

Abstract

TPS 741: Adverse birth outcomes 2, Exhibition Hall, Ground floor, August 28, 2019, 3:00 PM - 4:30 PM Background/Aim: Low birthweight is a leading cause of neonatal morbidity and mortality. Maternal factors, socioeconomic status, and ambient air pollution have been independently associated with low birthweight, but no studies have examined homelessness and Special Supplemental Nutrition Program for Women, Infants and Children (WIC) with air pollution. Our aim was to examine the associations and interactions between prenatal maternal homelessness, participation in WIC, and exposure to fine particulate matter (PM2.5) on birthweight in an urban cohort of low-income children in Boston. Methods: We included children recruited to the Boston-based Children’s HealthWatch cohort from 2007 through 2015 (n=3,619). Birthweight was obtained from electronic medical records. Information on maternal homelessness and WIC participation during pregnancy were provided via questionnaire. Prenatal PM2.5 exposures were calculated for each trimester. We built linear regression models adjusting for maternal age, body mass index (BMI), race/ethnicity, nativity, education, smoking, insurance, marital status, child gestational age and sex, seasonality, and median household income. We also examined interactions between PM2.5 and each of the covariates. Results: Being homeless during pregnancy was significantly associated with reduced birthweight (-45.5g, 95% CI: -85.4g, -5.5g), while participating in WIC was associated with increased birthweight (22.7g, 95% CI: -18.4g, 63.7g). Average PM2.5 during the second trimester was the most significant risk factor for reduced birthweight (-14g, 95% CI: -24.3, -3.6) compared to other PM2.5 exposure windows. The effect of PM2.5 during the second trimester on lower birthweight was stronger among immigrants, Hispanic or non-Hispanic Black mothers, single mothers, and mothers with lower educational attainment. Conclusions: Our study emphasizes the individual and synergistic roles of social and environmental stressors on birthweight, particularly the potential protective effect of participating in WIC. These findings can be used to direct interventions and policy to maximize a healthy start in life.