A Native American community with a 7% cesarean delivery rate: does case mix, ethnicity, or labor management explain the low rate?

PURPOSE Cesarean delivery rates vary widely across populations. Studying communities with low rates of cesarean delivery may identify practices that can lower the cesarean rate. METHODS A population-based historical cohort study included all pregnant women (N = 1132) from 1992 through 1996 in a predominantly Native American region of northwestern New Mexico known to have a high prevalence of gestational diabetes and preeclampsia. The outcomes studied included delivery type (eg, cesarean, operative vaginal, spontaneous vaginal), indication for cesarean delivery, presence of obstetrical risk factors, and use of labor induction or augmentation. RESULTS The cesarean delivery rate of the study group (7.3%) was only 35% of the 1996 US rate of 20.7%. Among study participants, the relative risk of a primary cesarean delivery for dystocia was 0.22 (95% CI, 0.14, 0.35). Trial of labor after cesarean delivery was attempted by 93% of study participants compared with 42% of women nationwide in 1994. The cesarean delivery rates for women with diabetes in pregnancy (11.5% versus 35.4%) and preeclampsia (14.8% versus 37.4%) were significantly lower than nationwide rates. Case-mix analysis comparison with a standardized population and comparison of standard (ie, term, singleton, vertex) primiparous women demonstrate that the low rate of cesarean delivery was not because of a lower prevalence of risk factors. CONCLUSIONS The community's low rate of cesarean delivery is primarily the result of a decreased use of cesarean delivery for labor dystocia and an almost universal acceptance of trial of labor after cesarean delivery. Cultural attitudes toward childbirth, design of the perinatal system, and genetic factors also may explain the low rate of cesarean delivery.