State-Level Abortion Policies and Infant Health Outcomes.

IMPORTANCE

Previous research has found associations between abortion policies and infant health. Differing methods complicate understanding which abortion policies matter for infant health.

OBJECTIVE

To examine associations between multiple state-level abortion policies and infant health.

DESIGN, SETTING, AND

PARTICIPANTS

This retrospective cohort study obtained birth certificate data and cohort-linked birth-infant death files and used logistic regression, adjusting for individual and state controls, state-year combination fixed effects, state-specific time trends, and standard errors clustered by state, with sensitivity analyses to identify robust findings. Participants included liveborn singleton births in the US from 2005 to 2022. Data were analyzed from January 2025, to June 7, 2026.

EXPOSURES: Eleven abortion policies.

MAIN OUTCOMES AND MEASURES: The primary outcomes were low birth weight (<2500 g), preterm birth (<37 weeks), low Apgar score (<7), and infant death.

RESULTS

Among 64 789 079 births, the mean (SD) maternal age was 28.2 (6.0) years; 6.5% (n = 4 193 951) of neonates were low birth weight, 10.3% (n = 6 664 535) were preterm, 1.8% (n = 1 142 835) had a low Apgar score, and 0.53% (n = 341 399) died; 1.6% (n = 1 006 123) of mothers had no prenatal care, and 23.6% (n = 14 449 109) had late prenatal care. Waiting periods (adjusted odds ratio [aOR], 0.97 [95% CI, 0.96-0.99]) and medication abortion in-person requirements (aOR, 0.98 [95% CI, 0.97-0.99]) were associated with decreased low birth weight. For clinician-type qualifications, ambiguity regarding advanced practice clinician provision was associated with decreased infant deaths (aOR, 0.69 [95% CI, 0.58-0.83]), physician-only requirements were associated with increased low birth weight (aOR, 1.03 [95% CI, 1.01-1.05]) and preterm birth (aOR, 1.05 [95% CI, 1.02-1.07]), and advance practice clinician provision of medication abortion only was associated with increased low birth weight (aOR, 1.03 [95% CI, 1.01-1.05]). The 6-week, fetal heartbeat bans were associated with increased preterm births (aOR, 1.04 [95% CI, 1.00-1.07]); the 20-week, fetal pain bans were associated with increased low Apgar score (aOR, 1.21 [95% CI, 1.06-1.38]); ultrasonography information requirements were associated with increased low Apgar scores (aOR, 1.12 [95% CI, 1.02-1.24]); private insurance bans were associated with increased preterm births (aOR, 1.04 [95% CI, 1.01-1.07]); and hospital transfer agreement requirements were associated with increased low birth weight (aOR, 1.02 [95% CI, 1.00-1.03]) and increased preterm births (aOR, 1.02 [95% CI, 1.00-1.03]).

CONCLUSIONS AND RELEVANCE: In this cohort study of US births, 5 abortion policies were associated with multiple increased adverse infant health outcomes, whereas 2 were associated with decreased low birth weight. Findings suggest multiple types of abortion policies-and not only total abortion bans-are relevant for infant health.