Unpacking Breastfeeding Disparities: Baby-Friendly Hospital Designation Associated with Reduced In-Hospital Exclusive Breastfeeding Disparity Attributed to Neighborhood Poverty.

Objectives: To examine US in-hospital exclusive breastfeeding (EBF) and the associations with Baby-Friendly designation and neighborhood sociodemographic factors.

Methods: Hospital data from the 2018 Maternity Practices in Infant Nutrition and Care survey were linked to hospital zip code tabulation area (ZCTA) sociodemographic data from the 2014-2018 American Community Survey (n = 2,024). The percentages of residents in the hospital ZCTA were dichotomized based on the relative mean percentage of the hospital's metropolitan area, which were exposure variables (high/low Black hospitals, high/low poverty hospitals, high/low educational attainment hospitals) along with Baby-Friendly designation. Using linear regression, we examined the associations and effect measure modification between Baby-Friendly designation and hospital sociodemographic factors with in-hospital EBF prevalence.

Results: US mean in-hospital EBF prevalence was 55.1%. Baby-Friendly designation was associated with 9.1% points higher in-hospital EBF prevalence compared to non-designated hospitals [95% confidence interval (CI): 7.0, 11.2]. High Black hospitals and high poverty hospitals were associated with lower EBF prevalence (difference= -3.3; 95% CI: -5.1, -1.4 and - 3.8; 95% CI: -5.7, -1.8). High educational attainment hospitals were associated with higher EBF prevalence (difference = 6.7; 95% CI: 4.1, 9.4). Baby-Friendly designation was associated with significant effect measure modification of the in-hospital EBF disparity attributed to neighborhood level poverty (4.0% points higher in high poverty/Baby-Friendly designated hospitals than high poverty/non-Baby-Friendly designated hospitals).