Abstract
Importance
The Society for Maternal-Fetal Medicine (SMFM) low-risk cesarean delivery metric aims to improve comparability, but the extent to which additional patient-level adjustment and reliability profiling alter hospital rankings is not well characterized.
Objectives
To evaluate how hospital cesarean delivery rankings differ across overall, SMFM-defined low-risk, and reliability-adjusted low-risk approaches, and to identify hospital characteristics associated with reliability-adjusted low-risk rates.
Design, Setting, and Participants
This cross-sectional study used data from the 2022 National Inpatient Sample, a nationally representative all-payer database, on individuals aged 11 to 55 years who were hospitalized for childbirth. Data were analyzed from October 2025 through June 2026.
Main Outcomes and Measures
Hospital cesarean delivery rates and rankings based on overall births, SMFM low-risk births (unadjusted), and empirical bayesian reliability-adjusted SMFM low-risk rates (mixed-effects logistic regression adjusting for age and obstetric comorbidities). Concordance was summarized by quartile cross-classification. Hospitals were classified as as-expected, lower-than-expected, or higher-than-expected on the basis of the 95% credible interval for the reliability-adjusted rate relative to the overall mean, and a hospital-level multivariable regression assessed characteristics associated with that rate.
Results
Of the 330 977 SMFM low-risk deliveries (mean [SD] maternal age, 29.0 [5.7] years) across 1231 hospitals, 45 471 (13.7%) were cesarean. Mean (SD) hospital cesarean delivery rates were 32.1% (5.4%) for overall cesarean delivery, 13.5% (4.2%) for SMFM low-risk cesarean delivery, and 10.4% (2.4%) for reliability-adjusted SMFM low-risk cesarean delivery. Quartile concordance between overall and unadjusted SMFM low-risk rankings was modest (61.7% agreement in the lowest quartile), whereas concordance between SMFM low-risk and reliability-adjusted rankings was higher (85.7% agreement in the lowest quartile). Based on 95% credible intervals, 1024 hospitals (83.2%) were classified as having as-expected rates of cesarean delivery, 81 (6.6%) as having lower-than-expected rates of cesarean delivery, and 126 (10.2%) as having higher-than-expected rates of cesarean delivery. In multivariable analysis, Midwestern (β = −1.13 percentage points; 95% CI, −1.56 to −0.70 percentage points) and Western (β = −1.26 percentage points; 95% CI, −1.68 to −0.83 percentage points) hospitals had lower reliability-adjusted rates than Northeastern hospitals.
Conclusions and Relevance
In this cross-sectional study of US hospitals, cesarean delivery rankings differed substantially between overall and SMFM low-risk denominators, highlighting limitations of overall rates for accountability. The high concordance between unadjusted and reliability-adjusted rankings suggests that the SMFM low-risk metric already captures most of the between-hospital signal. US region was the strongest correlate of reliability-adjusted rates.