Primary and Repeat Cesarean Deliveries: A Population-based Study in the United States, 1979–2010. Issue 4 (July 2017)

• Record Type: Journal Article
• Authors: Ananth, Cande V.; Friedman, Alexander M.; Keyes, Katherine M.; Lavery, Jessica A.; Hamilton, Ava; Wright, Jason D.
• Is Part Of: Epidemiology. Volume 28:Issue 4(2017)
• Publication Date: 2017-07
• Subjects: Epidemiology -- Periodicals; Epidemiology -- Environmental aspects -- Periodicals; Epidemiology -- Periodicals; 614.405
• DOI: 10.1097/EDE.0000000000000658
• Languages: English
• ISSNs: 1044-3983

Abstract

Abstract : Background: Despite the temporal increase in cesarean deliveries, the extent to which maternal age, period, and maternal birth cohorts may have contributed to these trends remains unknown. Methods: We performed an analysis of 123 million singleton deliveries in the United States (1979–2010). We estimated rate ratio (RR) with 95% confidence interval (CI) for primary and repeat cesarean deliveries. We examined changes in cesarean rates with weighted Poisson regression models across three time-scales: maternal age, year of delivery, and birth cohort (mother's birth year). Results: The primary cesarean rate increased by 68% (95% confidence interval [CI]: 67%, 69%) between 1979 (11.0%) and 2010 (18.5%). Repeat cesarean deliveries increased by 178% (95% CI: 176, 179) from 5.2% in 1979 to 14.4% in 2010. Cesarean rates increased with advancing age. Compared with 1979, the RR for the period effect in primary and repeat cesarean deliveries increased up to 1990, fell to a nadir at 1993, and began to rise thereafter. A small birth cohort effect was evident, with women born before 1950 at increased risk of primary cesarean; no cohort effect was seen for repeat cesarean deliveries. Adjustment for maternal BMI had a small effect on these findings. Period effects in primary cesarean were explained by a combination of trends in obesity and chronic hypertension, as well as demographic shifts over time. Conclusions: Maternal age and period appear to have important contributions to the temporal increase in the cesarean rates, although the effect of parity on these associations remains undetermined. Abstract : Supplemental Digital Content is available in the text.