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Poster Session 1

Category: Prematurity

Poster Session 1

(348) Association between mode of delivery and maternal and neonatal outcomes in periviable births with malpresentation

Wednesday, February 11, 2026

10:30 AM - 12:00 PM

Submitting Author and Presenting Author(s)

Sara E. Post, MD (she/her/hers)

MFM Fellow
University of Utah
Salt Lake City, Utah, United States

Coauthor(s)

AA

Amanda A. Allshouse, MS

Perinatal Biostatistician
University of Utah
Salt Lake City, Utah, United States
Ann M. Bruno, MD, MS (she/her/hers)

Assistant Professor
University of Utah
Salt Lake City, Utah, United States

Objective:
Active treatment of periviable neonates has increased in the past decade but data informing optimal mode of delivery are lacking. We aimed to evaluate the association between mode of delivery and maternal and neonatal outcomes in periviable births with malpresentation where resuscitation was intended.

Study Design:
This was a serial cross-sectional analysis of the National Vital Statistics System from 2016 to 2023. Singleton deliveries between 22w0d to 25w6d with malpresentation and intent for neonatal intervention (defined as one or more: surfactant therapy, immediate assisted ventilation, assisted ventilation >6 hours, neonatal intensive care unit [ICU] admission, antibiotic therapy) were included. Those with a known fetal anomaly or neonatal weight < 400 grams were excluded. The exposure was mode of delivery. The primary outcome was a composite maternal morbidity including blood transfusion, ICU admission and unplanned hysterectomy. Secondary outcomes were a composite neonatal morbidity defined as neonatal mortality or seizures. Multivariable modeling estimated the association between mode of delivery and outcomes with odds ratios and 95% confidence intervals reported.

Results:
Of 15,052 deliveries included, 2,301 (15.3%) were vaginal and 12,751 (84.7%) were cesarean. Baseline characteristics of those undergoing cesarean compared with vaginal delivery differed (Table 1). Cesarean delivery was associated with higher odds of maternal morbidity (4.5% vs 2.0%; OR 2.37, 95% CI 1.75-3.22; aOR 2.18, 95% CI 1.60-2.97; Table 2) with all components of the composite occurring more frequently in those undergoing cesarean delivery. Cesarean compared with vaginal delivery was associated with lower odds of neonatal morbidity (11.4% vs 28.4%; OR 0.33, 95% CI 0.29-0.36, aOR 0.42, 95% CI 0.38-0.47).

Conclusion:
In periviable births with malpresentation and intention to resuscitate, cesarean delivery was associated with increased maternal morbidity but decreased neonatal morbidity. Findings may inform patient counseling considering risks and benefits of both mother and perinate.