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CME Credit Offered
CME Credit Offered
Abstract Award
Abstract Award
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Poster Session 1

(210) Severe Maternal Morbidity and Mortality With Periviable and Preterm Birth

Thursday, January 30, 2025
10:30 AM – 12:30 PM  
Objective: Preterm and periviable birth are associated with adverse maternal outcomes, yet the association between severe maternal morbidity (SMM) and mortality risk with gestational age at delivery is limited. We aimed to assess the risk of SMM among those with periviable or preterm birth.

Study Design: This was a population-based cohort study of U.S. delivery hospitalizations from 2015-2021 using data from the National Inpatient Sample database. ICD-10 codes were used to identify delivery hospitalizations and gestational age at delivery. SMM was defined by CDC criteria (excluding transfusion). The primary outcome was the risk of SMM and mortality in patients with a periviable (20-25 weeks) or preterm (26-36 weeks) compared to term (37-42 weeks) birth. Secondary analyses included risk assessment by organ system-based SMM indicators. Subgroup analyses of outcomes were also performed for 3-week gestational age groupings (i.e. 20-22 weeks). Adjusted relative risks (aRR) were estimated using multivariable logistic regression analysis.

Results: Among 22,193,863 delivery hospitalizations, 0.6% were periviable, 9.4% preterm, and 90.0% term births. The rate and risk of SMM and mortality were significantly higher with periviable (4.4%, aRR 6.7, 95% CI 6.3-7.2 and 0.1%, aRR 27.0, 95% CI 17.1-42.6, respectively) and preterm birth (2.3%, aRR 3.5, 95% CI 3.4-3.7 and 0.03%, aRR 8.7, 95% CI 6.4-11.7, respectively) compared to term (0.5% and 0.0027%). Risk for nearly all individual morbidity indicators were increased with periviable or preterm birth (Figure 1). Periviable birth was associated with the highest risk of cardiovascular, renal, respiratory, sepsis, shock, and hemorrhagic events, while preterm birth had the highest risk of eclampsia. Previable deliveries (20-22 weeks) had a disproportionate burden of maternal death among those with an SMM event (Figure 2).

Conclusion: Periviable and preterm deliveries are associated with increased risk of SMM and mortality compared to term deliveries. This study highlights the substantial dual burden of preterm and periviable delivery on patients and their infants.