Maternal risk factor index and cesarean delivery among women with nulliparous, term, singleton, vertex deliveries, Texas, 2015.

Background: Cesarean delivery accounts for over one-third of the ~400 000 annual births in Texas, with first-time cesarean accounting for 20% of the overall cesareans. We examined associations of maternal medical comorbidities with cesarean delivery among nulliparous, term, singleton, vertex (NTSV) deliveries in Texas.
Methods: Nulliparous, term, singleton, vertex deliveries to women aged 15-49 years were identified using the 2015 Texas birth file (Center for Health Statistics, Texas Department of State Health Services). A risk factor index was constructed (score range 0-4), including preexisting/gestational diabetes mellitus, preexisting/gestational hypertension/eclampsia, infertility treatment, smoking during pregnancy, and prepregnancy overweight/obesity, and categorized as 0, 1, 2, and 3+ based on the number of risk factors present. Multivariable logistic regression analyses were conducted to examine associations between the categorized risk factor index and cesarean delivery, overall and by maternal race and ethnicity.
Results: Among the 114 535 NTSV deliveries in Texas in 2015, 27.2% were by cesarean. The most prevalent maternal risk among all deliveries was prepregnancy overweight/obesity (42.4%). The odds of cesarean delivery increased significantly with increasing number of risk factors [one risk factor: 1.72 (95% CI 1.67-1.78); two risk factors: 2.58 (95% CI 2.46-2.71); and three or more risk factors: 3.91 (95% CI 3.45-4.44)].
Discussion: In Texas in 2015, nearly half of NTSV deliveries had at least one maternal risk factor and the odds of cesarean delivery were significantly elevated for women with a higher risk index score. The findings from this study highlight the need for intervening during the preconception and interconception period as intrapartum care practices have an important influence on birth outcomes.
(© 2018 Wiley Periodicals, Inc.)