Comparisons of outcomes of maternity care by obstetricians and certified nurse-midwives

Abstract

To determine whether pregnancy outcomes differ by provider group when alternative explanations are taken into account. Pregnancy outcomes were compared for 710 women cared for by private obstetricians and 471 cared for by certified nurse-midwives. At intake, all women qualified for nurse-midwifery care. They were retained in their original group for analysis, even if they were later referred to physicians. Infant and maternal mortality, 30 clinical indicators, satisfaction with care, and monetary charges were studied. The study site's history and philosophy of honoring consumer choice of provider precluded random assignment, but multivariate analyses minimized the effects of multiple confounding factors. The statistical power was adequate for the study design. Significant differences (P < .05) between the obstetrician and nurse-midwife groups were found for seven clinically important outcomes: infant abrasions (7 versus 4%), infant remaining with mother for the entire hospital stay (15 versus 27%), third- or fourth-degree perineal laceration (23 versus 7%), number of complications (0.7 versus 0.4), satisfaction with care, average hospital charges ($5427 versus $4296), and average professional fee charges ($3425 versus $3237). When maternal risk, selection bias, and the medical intensiveness of care were controlled, the provider group did not continue to have an independent effect on infant abrasions, hemorrhage, and professional fee charges; when women's preferences were added, the difference in hospital charges disappeared. However, the provider group continued to have significant independent effects on the other four outcomes. Interaction effects were not significant. Although most outcomes were equally good, important differences between obstetrician and nurse-midwife care remained after multivariate analysis.