Severe maternal morbidity rates among patients who delivered at U.S. military hospitals between fiscal years 2019 and 2023 were significantly associated with annual hospital delivery volumes, U.S. Medicine reported in a study published in the Journal of Women’s Health. Researchers from the Uniformed Services University of the Health Sciences found that women giving birth at facilities in the upper-middle volume quartile faced different risk profiles for severe complications and 30-day readmissions compared to patients at lower- or higher-volume military treatment facilities.
Delivery Volumes and Severe Maternal Morbidity Across 29 Military Hospitals
Investigators analyzed healthcare claims data from 137,266 obstetric deliveries performed across 29 military hospitals during the five-year study period. Eligible beneficiaries included active-duty service members, dependent family members, and retirees aged 15 to 54 years old. The research team grouped military hospitals into four quartiles based on their average annual obstetric volume using International Classification of Diseases-10 (ICD-10) and Medicare Severity-Diagnosis Related Group codes.
The analysis revealed that patients delivering at hospitals in the lowest, lower-middle, and highest volume quartiles experienced significantly lower (19 to 30%) odds of severe maternal morbidity compared to those delivering at upper-middle quartile hospitals. Severe maternal morbidity was tracked using 21 specific ICD-10 indicators, such as blood transfusions, acute myocardial infarction, eclampsia, and cardiac arrest.
Conversely, patients delivering at lower and lower-middle quartile facilities faced significantly higher (29 to 46%) odds of 30-day postpartum readmissions compared to the upper-middle quartile group. The study found no statistically significant difference in 30-day readmission odds for patients treated at hospitals in the highest volume quartile.
Pandemic and restructuring shift maternal care landscape
The new findings diverge from an earlier baseline study published in Military Medicine in 2022, which examined MHS delivery data from fiscal years 2015 to 2018. Co-author Tracey Perez Koehlmoos, PhD, MHA, a professor and director of the Center for Health Services Research at USU, noted that the maternal care landscape shifted substantially between the two study periods.
Given the administrative restructuring, the rollout of a new electronic health record, the disruptions of the COVID-19 pandemic and troubling national trends in maternal health, we needed to know how these combined forces affected care,
Koehlmoos told U.S. Medicine. She explained that simultaneous organizational changes under the Defense Health Agency and pandemic-related operational challenges likely compounded clinical trends during the 2019–2023 window.
From fiscal years 2016 and 2018, overall rates of severe maternal morbidity and subsequent 30-day postpartum readmissions among MHS beneficiaries were lower than in the overall civilian population.
Research aims to improve clinical outcomes for military patients
Study authors recommend that future research identify modifiable risk factors to improve clinical outcomes across all obstetric volume quartiles, with particular attention directed toward facilities in the lowest and lower-middle volume tiers. The findings aim to raise awareness among MHS clinicians regarding rising postpartum readmission rates and severe maternal morbidity indicators.
Our findings show that military treatment facility delivery volume may have impacted severe maternal outcomes and post-discharge readmission rates,
Koehlmoos said. As birth rates decline both across the Military Health System and nationwide, research like this provides program planners and healthcare leaders with the evidence they need to identify where resources and support are needed most.
Frequently Asked Questions About Military Hospital Delivery Studies
Which patients were included in the Uniformed Services University delivery study?
The cross-sectional study evaluated healthcare claims data from MHS beneficiary women between 15 and 54 years old who gave birth at U.S. military hospitals from fiscal year 2019 through fiscal year 2023. Eligible participants included active-duty service members, dependent family members, and retirees.
How was severe maternal morbidity measured in the research?
Researchers measured severe maternal morbidity using 21 specific ICD-10 indicators recorded in patient delivery files. These clinical indicators included blood transfusions, cardiac arrest, acute myocardial infarction, hysterectomy, and eclampsia.
What defines a 30-day postpartum readmission in this data?
Postpartum readmissions were tracked as any maternal readmission to the exact same military hospital within 30 days of the original delivery discharge date. Readmissions occurring at a different military hospital were excluded from this specific metric.
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