Cesarean delivery and postpartum mortality among primiparas in Washington State, 1987-1996

Objective: To examine the association between delivery method and mortality within 6 months of delivery among primiparas. Methods: We conducted a population-based, retrospective cohort analysis usi ng statewide, maternally linked birth certificate, hospital discharge, and death certificate data. The present cohort was all primiparas who gave birt h to liveborn infants in civilian hospitals in Washington State from Januar y 1, 1987 through December 31, 1996 (n = 265,471). Odd ratios (OR) and 95% confidence intervals (CI) were calculated for overall mortality, pregnancy- related mortality, and pregnancy-unrelated mortality associated with delive ry method. Results: Thirty-two women (12.1 per 100,000 singleton live births) died wit hin 6 months of delivery of their first child. Eleven of 32 deaths were pre gnancy related (4.1 per 100,000 singleton live births, 95% CI 1.6, 6.5), an d 21 of the 32 deaths were not pregnancy related (7.9 per 100,000 singleton live births, 95% CI 4.5, 11.3). The pregnancy-related mortality rate was h igher among women delivered by cesarean (10.3/100,000) than among women del ivered vaginally (2.4/100,000). In logistic regression analyses, women who had cesarean delivery were not at significantly higher risk of death overal l after adjustment for maternal age (OR 1.7, 95% CI 0.3, 3.6), pregnancy- r elated death after adjustment for maternal age and severe preeclampsia (OR 2.2 95% CI 0.6, 7.9), or pregnancy-unrelated death after adjustment for mat ernal age and marital status (OR 0.9, 95% CI 0.3, 2.7), relative to women w ho had vaginal delivery. Conclusion: Cesarean delivery might be a marker for serious preexisting mor bidities associated with increased mortality risk rather than a risk factor for death in and of itself. Data from additional sources such as medical r ecords and autopsy reports are necessary to disentangle preexisting mortali ty risk from risk associated solely with delivery method. (Obstet Gynecol 2 001;97:169-74. (C) 2001 by The American College of Obstetricians and Gyneco logists.).