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Poster Session 1

Category: Health Equity/Community Health

Poster Session 1

(339) Adverse Birth Outcomes Among American Indian and Alaska Native Women Living on Reservations

Wednesday, February 11, 2026

10:30 AM - 12:00 PM

Submitting Author and Presenting Author(s)

Ryan Duggal, MD

University of California San Francisco
University of California San Francisco, California, United States

Coauthor(s)

AS

Alexandra Sundermann, MD, PhD

Vanderbilt University Medical Center
Vanderbilt University Medical Center, Tennessee, United States
MK

Michael Kramer, PhD

Mercer University School of Medicine
Mercer School of Medicine, Georgia, United States

Objective:
To compare adverse birth outcomes (ABOs) among American Indian and Alaska Native (AI/AN) women living on reservations with non-indigenous people living in the same counties.

Study Design:
Using 2018-2022 restricted natality data from the National Vital Statistics System (NVSS) the following ABOs were analyzed: maternal morbidity, preterm birth, low birth weight, and NICU admission. By linking Public Use Microdata Areas (PUMAs) to counties and reservations using 5-year American Community Survey (ACS) microdata, geographic shapefiles, and age-specific fertility rates, births were estimated among AI/AN women living on a reservation. PUMAs were mapped to county race-specific population data to estimate the probability that someone identifying as AI/AN lived on the reservation; using a data-driven probability threshold, each AI/AN woman with a birth was determined to be living either on or off reservation in each county. Modified Poisson regression was used to estimate crude and adjusted relative risks (aRRs) for the association between ABOs and reservation status.

Results:
There were 4,091,162 births in 548 counties containing reservations included in this cohort. Of these, 35,778 women were identified as AI/AN with a high probability of living on a reservation. Maternal morbidity and preterm birth for AI/AN women living on reservations were significantly higher (aRR 2.45, 95% confidence intervals [CI] 2.24–2.69; aRR 1.18, 95% CI 1.15–1.21) in both unadjusted and adjusted analysis than for non-AI/AN women living in the same counties. There was no difference in the unadjusted or adjusted risk for low birth weight or NICU admission (aRR 0.96, 95% CI 0.92–1.00; aRR 0.99, 95% 0.95–1.02) between the groups.

Conclusion:
AI/AN women living on reservations in this cohort had higher rates of maternal morbidity and preterm birth than non-AI/AN women in the same counties but not living on reservations. These disparities highlight the urgent need for targeted, community-informed maternal health interventions on reservations.