Effect of preexisting chronic disease on primary cesarean delivery rates by race for births in U.S. military hospitals, 1999-2002.

BACKGROUND: A previous study of the United States Department of Defense healthcare beneficiaries reported elevated cesarean delivery rates for black and Asian women relative to white women that were independent of maternal socioeconomic status. This finding suggests that other maternal factors may explain the elevated rates. The purpose of this study was to examine the prevalence of specific chronic diseases identified as risk factors for complications during pregnancy, labor, and delivery, and to explore the strength of each disease to predict a cesarean outcome.

METHODS: United States military hospital discharge records from 1999 to 2002 for singleton births to women without a previous cesarean were used to calculate primary cesarean and chronic disease rates for diabetes, hypertension, cardiovascular disease, renal disease, anemia, asthma, sexually transmitted diseases, and substance abuse. Stepwise logistic regression was used to calculate adjusted odds ratios for dichotomized race and chronic disease indicators for five maternal age groups using the chi2 difference (p < 0.05) to identify significant variables for inclusion in the model. Primary cesarean delivery rates were then adjusted for the presence of chronic diseases that were significantly associated with a cesarean outcome.

RESULTS: Diabetes, genital herpes, and hypertension were significant predictors of cesarean use among all maternal age groups. Cardiovascular disease, renal disease, asthma, and anemia were predictors in some age groups. The remaining disease conditions were not significant predictors for cesarean delivery. Adjustment of cesarean rates for these chronic diseases did not significantly alter the differences in primary cesarean rates for black and Asian mothers relative to white mothers.

CONCLUSIONS: The presence of certain chronic conditions before pregnancy may increase the likelihood that a woman will deliver by cesarean section. Adjustment of cesarean rates for the presence of these chronic diseases, however, does not account for the difference in cesarean rates observed for white and minority mothers in the study population. The potential for underreporting of chronic diseases complicates a true assessment of the impact of chronic disease on cesarean delivery rate variations between white and minority women.