title: The effect of health maintenance organization vs commercial insurance status on obstetrical management and outcome.
abstract: OBJECTIVE
  To compare obstetrical management and birth outcomes between patients with health maintenance organization (HMO) insurance and those with private commercial insurance.
  
  
  METHODS
  Retrospective population-based cohort study.
  
  
  METHODS
  King County, Washington.
  
  
  METHODS
  Among newborns delivered in 1992 and 1993, a random sample of 4000 birth records listing HMO insurance for prenatal care was compared with a random sample of 4000 birth records listing private commercial insurance as the primary coverage.
  
  
  METHODS
  Use of ultrasonography and amniocentesis; rate of primary cesarean section performed; adequacy of prenatal care; incidence of maternal medical complications, low birth weight, and congenital malformations; and length of hospital stay.
  
  
  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 less 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 anomalies were observed. Among women without obstetrical risk factors, HMO-insured mothers were at an increased risk of labor and delivery complications (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
  Patients with HMO insurance have improved access to prenatal care and screening when compared with privately insured patients. The reasons for increased risks of abnormal maternal and infant outcomes observed among a subset of HMO-insured patients are unclear. A study with more detailed prospective data collection is warranted.
authors.affiliation: Department of Pediatrics, School of Medicine, and Epidemiology, University of Washington, Seattle, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Aitken
authors.forename: C R
authors.initials: CR
authors.lastname: Warden
authors.forename: C W
authors.initials: CW
authors.lastname: Critchlow
mesh_terms: D005260:Female; D006279:Health Maintenance Organizations; D006801:Humans; D007348:Insurance, Health; D009774:Obstetrics; D011247:Pregnancy; D011256:Pregnancy Outcome; D017149:Private Sector; D012189:Retrospective Studies; D014861:Washington