Breast Milk Feeding Outcomes after Expansion of Military Parental Leave: A Retrospective Cohort Study of Active-Duty Mothers

Background: Breast milk feeding is the recommended standard for infant nutrition. Active-duty (AD) mothers in the U.S. military face unique barriers to sustained breast milk feeding. The Department of Defense expanded the Military Parental Leave Program in January 2023, increasing total leave for birthing parents from 12 to 18–20 weeks. Objective: To explore whether extension of military parental leave was associated with trends in breast milk feeding duration among AD mothers at a single U.S. military medical treatment facility. Methods: This retrospective cohort study included all viable infants born to AD mothers between February 1, 2022, and June 30, 2023. Dyads were categorized into two epochs: before (February 1 to October 3, 2022) and after (October 4, 2022, to June 30, 2023) implementation of the updated policy. Breast milk feeding initiation, exclusivity, and duration through 6 months were analyzed descriptively. Results: Among 309 infants, representing 22% of all deliveries, no statistically significant differences were observed in exclusive or any breast milk feeding rates before and after policy change. Exclusive breast milk feeding rates exceeded those reported following the 2016 leave extension. There were higher rates of exclusive and any breast milk feeding in mothers who are officers compared to those who are enlisted. Additionally, more enlisted mothers transitioned to exclusive formula feeding by 6 months (43.8% versus 19.8%). Conclusions: Following extension of military parental leave, breast milk feeding outcomes were maintained, while persistent rank-based disparities remained, underscoring the need for continued evaluation and targeted support for enlisted AD mothers.