Abstract
Identifying key factors behind persistently high cesarean rates over the past 15 years is challenging due to inconsistent documentation of primary indications, overlapping risk factors, and evolving clinical standards. The modified Robson classification helps standardize comparisons across populations. Cesarean rates by modified Robson class were compared using National Vital Statistics data from 2009, when the cesarean rate peaked, to the most recent data available in 2023. In 6 of the 11 categories, the rate of cesarean decreased: nulliparous spontaneous, nulliparous induced, multiparous spontaneous, previous cesarean, twins and higher-order multiples, and unclassified. Cesarean rates increased in 2 categories: breech and other noncephalic presentation and preterm. Cesarean rates stayed the same in 3 categories: nulliparous cesarean, multiparous induced, and multiparous cesarean. Data from the Consortium on Safe Labor highlight 2 major contributors to cesarean rates: women with previous cesareans and nulliparous with induced labor. From 2009 to 2023, intrapartum cesareans in the previous cesarean group declined (31.6% to 26.4%), yet the previous cesarean group remained the highest contributor to the total cesarean rate and its proportion of total cesareans increased (27.5% to 31.2%). Similarly, intrapartum cesareans among nulliparas with induced labor decreased slightly (26.2% to 24.9%), yet its proportion of total cesareans increased (7.7% to 10.4%). Meanwhile, risk factors like advanced maternal age (≥35) and higher body mass index (≥25) became more common. After adjusting for these factors, logistic regression showed a 62% lower odds of cesarean in the previous cesarean group (adjusted odds ratio, 0.38; 95% confidence interval, 0.37–0.38) and an 30% decrease in nulliparous with induced labor (adjusted odds ratio, 0.70; 95% confidence interval, 0.69–0.71) by 2023, suggesting improved risk management. Efforts to reduce unnecessary cesareans—such as promoting vaginal births after cesarean and public reporting—may be working, although further research accounting for maternal comorbidities and in relation to neonatal outcomes is needed. Trends vary by subgroup, with some rates rising, others falling, or remaining stable. Disaggregated data, rather than global rates, offer clearer insights for targeted interventions.