Spillover Effects of Prenatal Care Coordination on Older Siblings Beyond the Mother-Infant Dyad

Background: Pregnancy care coordination increases preventive care receipt for mothers and infants. Whether such services affect other family members' health care is unknown. Objective: To estimate the spillover effect of maternal exposure to Wisconsin Medicaid's Prenatal Care Coordination (PNCC) program during pregnancy with a younger sibling on the preventive care receipt for an older child. Research Design: Gain-score regressions - a sibling fixed effects strategy - estimated spillover effects while controlling for unobserved family-level confounders. Subjects: Data came from a longitudinal cohort of linked Wisconsin birth records and Medicaid claims. We sampled 21,332 sibling pairs (one older; one younger) who were born during 2008-2015, who were <4 years apart in age, and whose births were Medicaid-covered. In all, 4773 (22.4%) mothers received PNCC during pregnancy with the younger sibling. Measures: The exposure was maternal PNCC receipt during pregnancy with the younger sibling (none; any). The outcome was the older sibling's number of preventive care visits or preventive care services in the younger sibling's first year of life. Results: Overall, maternal exposure to PNCC during pregnancy with the younger sibling did not affect older siblings' preventive care. However, among siblings who were 3 to <4 years apart in age, there was a positive spillover on the older sibling's receipt of care by 0.26 visits (95% CI: 0.11, 0.40 visits) and by 0.34 services (95% CI: 0.12, 0.55 services). Conclusion: PNCC may only have spillover effects on siblings' preventive care in selected subpopulations but not in the broader population of Wisconsin families.