Effects of maternal characteristics on cesarean delivery rates among U.S. Department of Defense healthcare beneficiaries, 1996-2002.

BACKGROUND: National rates of cesarean birth continue a three decade-long escalation, despite widespread recognition that a reduction in the use of the procedure is a continuing appropriate public health goal, as evidenced by the Healthy People 2010 reduction targets. Nonclinical factors associated with cesarean delivery include maternal age, race, socioeconomic status, and insurance coverage. This study compared cesarean delivery rates and trends for the U.S. Department of Defense healthcare beneficiary population from 1996 to 2002 with those observed nationally, and assessed the association of these nonclinical factors with cesarean rate variation in the U.S. Department of Defense healthcare beneficiary population.

METHODS: Hospital discharge and claims records for babies born in the military and civilian hospitals that comprise the Department of Defense healthcare network were used to calculate total and primary cesarean delivery rates and vaginal birth after cesarean (VBAC) rates from 1996 to 2002. Annual cesarean rates for subgroups defined by maternal age, race, and socioeconomic status were calculated to examine rate variations and rate trends within the study population. Pooled data from 1999 to 2002 were used to compare rates across socioeconomic status, stratified by age and race. Statistical significance of the differences calculated for subgroups was assessed using chi-square.

RESULTS: Total and primary cesarean delivery rates among the U.S. Department of Defense population were lower than those reported nationally for every year examined. Cesarean delivery and VBAC rate trends in the national and Department of Defense populations were similar. Within the Department of Defense population, total cesarean delivery increased with increasing maternal age and was more highly associated with racial minorities relative to white women. The higher socioeconomic subgroup (defined as active duty, retired, and warrant officers and their families in this study) was generally associated with reduced cesarean delivery rates.

CONCLUSIONS: Cesarean deliveries are performed less frequently for the U.S. Department of Defense healthcare beneficiary population relative to the national population. Associations between socioeconomic factors and cesarean rates reported for the national population were not apparent in the study population. The consistent pattern of rate variation across racial subgroups in the Department of Defense population suggests that factors beyond those examined in this study are needed to explain the elevated cesarean rates for racial minorities.