Cesarean Delivery Trends Among Patients at Low Risk for Cesarean Delivery in the US, 2000–2019
Authors: Frappaolo Anna M. , Logue Teresa C. , Goffman Dena , Nathan Lisa M. , Sheen Jean-Ju , Andrikopoulou Maria , Wen Timothy , D'Alton Mary E. , Friedman Alexander M. 
Published: September 2023

ABSTRACT
Cesarean delivery is a method of improving outcomes for both mothers and neonates when there are medical complications to vaginal delivery. When used unnecessarily, however, it causes increased risks for adverse outcomes as a major surgery. Limited data and investigations have prevented some previous analyses of trends in cesarean deliveries, especially when classifying them as necessary or unnecessary. This study was designed to determine temporal trends in cesarean deliveries among low-risk patients over a 20-year period and to analyze trends in specific cesarean delivery indications.
This study was designed as a repeated cross-sectional analysis among patients at low risk for cesarean delivery. The authors utilized the National Inpatient Sample data set, and then patients with conditions previously associated with an increased risk of cesarean delivery (eg, obesity) were excluded. Primary outcomes included temporal trends in the number of cesarean deliveries, as well as trends related to diagnoses of nonreassuring fetal status, labor arrest, or obstructed labor (including disproportion).
Between 2000 and 2019, 40,517,867 eligible low-risk deliveries were identified. Of these, 4,885,716 were cesarean deliveries. The overall rate of cesarean delivery increased between 2000 and 2009 (from 9.7% to 13.9%) and then decreased between 2012 and 2019 (from 13% to 11.1%). The average annual percentage change (AAPC) from 2000 to 2005 was 6.4% (95% confidence interval [CI], 5.2%–7.6%), with a plateau from 2005 to 2009 (AAPC, 1.2%; 95% CI, −1.2% to 3.7%) and then a decrease from 2009 to 2019 (AAPC, −2.2%; 95% CI, −2.7% to −1.8%). Deliveries associated with the diagnosis of nonreassuring fetal status increased between 2000 and 2019 (AAPC, 2.1%; 95% CI, 1.7%–2.5%); those associated with labor arrest peaked in 2009 at 4.8% and then decreased to 2.7% in 2019 (AAPC 2009–2019, −5.6%; 95% CI, −6.6% to −4.6%). In contrast, cesarean deliveries due to obstructed labor continuously decreased from 2000 to 2019 (AAPC, −8.6%; 95% CI, −10.0% to −7.1%).
After accounting for demographic and hospital characteristics, analysis showed that patients were at increased risk of cesarean delivery if they were between 35 and 39 years of age compared with the younger group of 25 to 29 years (adjusted odds ratio [aOR], 1.27; 95% CI, 1.25–1.28), if they delivered at a hospital in the South versus the Northeast (aOR, 1.11; 95% CI, 1.07–1.15), and if they were non-Hispanic Black versus non-Hispanic White (aOR, 1.23; 95% CI, 1.20–1.25).
Overall trends showed increasing rates of cesarean delivery in the first 10 years of the study, but then decreasing rates for the final 10 years. Rates associated with diagnoses of nonreassuring fetal status increased over the study period, and those associated with labor arrest or obstruction decreased. The increase of cesarean delivery due to nonreassuring fetal status when compared with the overall trend of decreasing cesarean deliveries indicates a possible clinical oversight as the interpretation of nonreassuring fetal status can differ based on provider and facility. Some guidelines are in place for determining nonreassuring fetal status, but interpretation of the guidelines and sometimes the guidelines themselves have changed over the time period of this study. This increase is potentially attributable to the changes in requirements or the interpretation of them and should be more fully investigated. Future research should focus on more accurately identifying diagnoses of nonreassuring fetal status to reduce the number of unnecessary cesarean deliveries while improving the outcomes of those that truly need cesarean deliveries.