Investigating racial differences in risk factors for primary cesarean delivery.

ABSTRACT

OBJECTIVE: The objective of the study was to investigate differences in sociodemographic, medical, and obstetric risk factors for primary cesarean delivery between black and white women. STUDY DESIGN: We conducted a retrospective cohort study among 25,251 black and white women delivering a live, singleton infant with vertex presentation at a large, regional hospital between 2004 and 2010. Demographic and clinical data were derived from electronic hospital records. Differences in risk factors for primary cesarean delivery were analyzed using a modified Poisson regression approach stratified by race and parity. RESULTS: Black and white women had a primary cesarean delivery rate of 24.7% and 22.2%, respectively (P < .001). Black women had an increased risk of cesarean delivery after adjusting for sociodemographic and clinical risk factors (adjusted relative risk [RR], 1.23; 95% confidence interval [CI], 1.17-1.29). Among nulliparas, labor induction had a greater effect on cesarean delivery for black women (adjusted RR, 1.32; 95% CI, 1.20-1.44) than for white women (adjusted RR, 1.13; 95% CI, 1.07-1.20). Among multiparas, labor induction reduced the risk of cesarean delivery for white women (adjusted RR, 0.63; 95% CI, 0.55-0.72), whereas no association was observed for black women (adjusted RR, 1.08; 95% CI, 0.92-1.28). Advanced maternal age was a stronger risk factor for black women (adjusted RR, 1.72; 95% CI, 1.43-2.08) than for white women (adjusted RR, 1.30; 95% CI, 1.11-1.52) among multiparas only. Among nulliparas, delivery at 37-38 weeks' gestation reduced the risk of cesarean delivery for black women (adjusted RR, 0.82; 95% CI, 0.73-0.92), whereas no association was observed for white women (adjusted RR, 0.96; 95% CI, 0.90-1.04). CONCLUSION: Labor induction, among nulliparous women, and advanced maternal age, among multiparous women, are stronger risk factors for primary cesarean delivery for black women than for white women.