THE EFFECT OF HEALTH MAINTENANCE ORGANIZATION VS COMMERCIAL INSURANCESTATUS ON OBSTETRICAL MANAGEMENT AND OUTCOME

Objective: To compare obstetrical management and birth outcomes betwee n patients with health maintenance organization (HMO) insurance and th ose with private commercial insurance. Design: Retrospective, populati on-based cohort study. Setting: King County, Washington. Patients: Amo ng newborns delivered in 1992 and 1993, a random sample of 4000 birth records listing HMO insurance for prenatal care was compared with a ra ndom sample of 4000 birth records listing private commercial insurance as the primary coverage. Main Outcome Measures: Use of ultrasonograph y and amniocentesis; rate of primary cesarean section performed; adequ acy of prenatal care; incidence of maternal medical complications, low birth weight, and con genital malformations; and length of hospital s tay. Results: Women covered by HMO compared with commercial insurance were more likely to undergo ultrasonography (relative risk [RR], 1.4; 95% confidence interval [CI], 1.3-1.4). Inadequate prenatal care was l ess frequent among HMO-insured patients (RR, 0.6; 95% CI, 0.5-0.7), as was the incidence of birth weight below 2500 g (RR, 0.7; 95% CI, 0.6- 0.9). No differences in rates of cesarean section and congenital anoma lies were observed. Among women without obstetrical risk factors, HMO- insured mothers were at an increased risk of labor and delivery compli cations (RR, 1.4; 95% CI, 1.3-1.5); their infants were at an increased risk of infant distress (RR, 1.8; 95% CI, 1.5-2.2). Conclusions: Pati ents with HMO insurance have improved access to prenatal care and scre ening when compared with privately insured patients. The reasons for i ncreased risks of abnormal maternal and infant outcomes observed among a subset of HMO-insured patients are unclear. A study with more detai led prospective data collection is warranted.