Maternal Outcomes Among Periviable Births by Cesarean Delivery.

Importance: Contemporary estimates of adverse maternal outcomes associated with periviable cesarean delivery are important for patient counseling and clinical decision-making. Objective: To characterize trends, risks factors, and adverse maternal outcomes associated with periviable cesarean delivery at 22 weeks 0 days to 25 weeks 6 days of gestation. Design, Setting, and Participants: This cross-sectional study analyzed adverse maternal outcomes among singleton periviable delivery hospitalizations at 22 weeks 0 days to 25 weeks 6 days' gestational age (GA). Hospitalizations were identified using the US National Inpatient Sample for a 7-year period (2016-2022). Data analysis was performed between March and December 2025. Exposures: The exposure of interest was periviable vaginal vs cesarean delivery. Clinical, demographic, and hospital factors associated with periviable cesarean delivery were also analyzed. Main Outcomes and Measures: The primary end point was risk for a range of adverse maternal outcomes, including nontransfusion severe maternal morbidity, transfusion, a critical care composite, a wound complications composite, venous thromboembolism, postpartum hemorrhage, endometritis, and peripartum hysterectomy. Unadjusted and adjusted logistic regression models for adverse outcomes were performed. Regression estimates were presented as unadjusted and adjusted odds ratios (AOR) with 95% CIs and as adjusted prevalence differences with 95% CIs. Trends were analyzed using joinpoint regression, and estimates were presented as the average annual percent change (AAPC). Results: Of an estimated 98 240 periviable deliveries identified, 39 595 (40.3%) were by cesarean delivery (median [IQR] maternal age, 29.9 [24.1-33.4] years) and 58 645 (59.7%) were by vaginal delivery (median [IQR] maternal age, 28.2 [23.3-32.9] years). Cesarean delivery rates increased with advancing GA (13.1% of births at 22 weeks 0 days to 22 weeks 6 days; 37.4% of births at 23 weeks 0 days to 23 weeks 6 days; 52.1 % of births at 24 weeks 0 days to 24 weeks 6 days; 54.8% of births at 25 weeks 0 days to 25 weeks 6 days) and were more common in the setting of a prior cesarean delivery (AOR, 2.57; 95% CI, 2.35-2.82) or hypertensive disorder of pregnancy (AOR, 3.19; 95% CI, 2.88-3.53), and at urban teaching hospitals vs rural hospitals (AOR, 1.49; 95% CI, 1.26-1.76). Cesarean delivery was less likely in the setting of fetal growth restriction (AOR, 0.47; 95% CI, 0.42-0.53), preterm premature rupture of membranes (AOR, 0.50; 95% CI, 0.46-0.54), and preterm labor (AOR, 0.79; 95% CI, 0.68-0.91). Sensitivity analyses incorporating indication for cesarean delivery yielded similar results. Compared with vaginal delivery, cesarean delivery was associated with increased adjusted odds of nontransfusion severe maternal morbidity (AOR, 2.50; 95% CI, 2.10-2.97), transfusion (AOR, 2.44; 95% CI, 2.03-2.94), a critical care composite (AOR, 3.41; 95% CI, 2.25-5.17), and venous thromboembolism (AOR, 2.44; 95% CI, 1.27-4.70). In trends analysis, the proportion of periviable deliveries occurring by cesarean delivery increased significantly over the study period (AAPC, 1.6%; 95% CI, 0.7%-2.4%). Conclusions and Relevance: In this cross-sectional study of periviable births, the proportion of periviable deliveries by cesarean increased over time. Compared with vaginal delivery, periviable cesarean delivery was associated with an increased risk for adverse maternal outcomes and severe maternal morbidity.