113 Advanced maternal age and its impact on the NTSV cesarean delivery rate

Abstract

The nulliparous, term, singleton, vertex cesarean delivery (NTSV CD) rate is an established quality measure, with the national target set below 24% based on the Healthy People initiative. While advanced maternal age (AMA) is associated with a higher rate of cesarean delivery in general, its impact on the NTSV CD rate is unclear. Therefore, we sought to determine if AMA is associated with higher NTSV CD rates at our institution. Cohort study of women with NTSV pregnancies undergoing a trial of labor at our institution from August 2016 to August 2017. Those undergoing an elective cesarean delivery were excluded. The primary exposure was maternal age ≥35 years (AMA), and the primary outcome measure was the NTSV CD rate. Secondary outcomes were the NTSV CD rate by age category (<20, 20-24, 25-29, 30-34, 35-39 and ≥40 years). Confounders assessed included gestational age, BMI, race/ethnicity, insurance status and labor induction. We conducted analyses with Chi-squared tests and multivariable logistic regression, with α=0.05. We evaluated 2,862 women with NTSV pregnancies undergoing a trial of labor, of whom 931 (33%) were AMA and 498 (17%) had a cesarean delivery. Compared to the maternal age distribution of NTSV deliveries in the United States, our population was skewed towards more women with AMA (33% vs 10%, P<0.001), Table 1. At our institution, the NTSV CD rate was significantly higher in women ages 35 and over compared to those less than age 35 (24% vs 14%, P<0.001), Table 2. In addition, the NTSV CD rate increased with advancing maternal age category [<20 (0%), 20-24 (9%), 25-29 (13%), 30-34 (16%), 35-39 (22%) and ≥40 (31%), P<0.001]. The odds of NTSV CD was significantly greater in women ages 35 and over, even after adjustment for gestational age, BMI, race/ethnicity, insurance status and labor induction (aOR 1.8, 95% CI 1.5-2.2, P<0.001). The NTSV CD rate was significantly higher among women ages 35 and over undergoing a trial of labor at our institution. Maternal age distribution should be considered when assessing NTSV CD rates at individual institutions.View Large Image Figure ViewerDownload Hi-res image Download (PPT)