The Influence of Detailed Maternal Ethnicity on Cesarean Delivery: Findings from the US Birth Certificate in the State of Massachusetts

Background: Our objective was to examine the likelihood of primary cesarean delivery for women at low risk for the procedure in Massachusetts. Methods: Birth certificate data for all births from 1996 to 2010 that were nulliparous, term, singleton, and vertex (NTSV; N = 427,393) were used to conduct logistic regression models to assess the likelihood of a cesarean delivery for each of the 31 ethnic groups relative to self-identified American mothers. The results were compared with broad classifications of race/ethnicity more commonly employed in research. Results: While 23.3 percent of American women had primary cesarean deliveries, cesarean delivery rates varied from 12.9 percent for Cambodian to 32.4 percent for Nigerian women. Women from 21 of 30 ethnic groups had higher odds of a primary cesarean (range of adjusted odds ratios [AORs] 1.09-1.77), while only Chinese, Cambodian, and Japanese women had lower odds (range of AORs 0.66-0.92), compared with self-identified Americans. Using broad race/ethnicity categories, Non-Hispanic black, Hispanic, and Other women had higher odds of cesarean delivery relative to Non-Hispanic white women (range of AORs 1.12-1.47), while there were no differences for Asian or Pacific Islander women. Conclusions: Detailed maternal ethnicity explains the variation in NTSV cesarean delivery rates better than broad race/ethnicity categories. Different patterns of cesarean delivery between ethnic groups suggest cultural specificity related to birth culture.