title: A comparison of heterotopic and intrauterine-only pregnancy outcomes after assisted reproductive technologies in the United States from 1999 to 2002.
abstract: OBJECTIVE
  To compare the risk for adverse outcomes of pregnancies between heterotopic (defined as a simultaneous intrauterine and ectopic pregnancy) and intrauterine-only pregnancies achieved through assisted reproductive technologies (ARTs).
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  ART centers in the United States.
  
  
  METHODS
  Patients were studied in terms of cycles reported to the population-based United States ART Registry, which included 207 heterotopic and 132,660 intrauterine-only pregnancies reported from 1999 to 2002.
  
  
  METHODS
  None.
  
  
  METHODS
  Outcomes of heterotopic and intrauterine-only pregnancies and deliveries (spontaneous abortion, induced abortion, still birth, and live birth). Perinatal outcomes (preterm, low birth weight [LBW], preterm LBW, and term LBW) for live-birth deliveries were also assessed.
  
  
  RESULTS
  Heterotopic pregnancies were more likely to end in spontaneous (relative risk = 2.05; 95% confidence interval, 1.67-2.51) or induced (relative risk = 10.28, 95% confidence interval, 6.76-15.65) abortions than were intrauterine-only pregnancies. There was no significant difference in perinatal outcomes studied, regardless of adjustment for maternal age, infertility diagnosis, previous live births, and type of ART procedure.
  
  
  CONCLUSIONS
  Heterotopic pregnancies were more likely to result in spontaneous or induced abortions than were intrauterine-only pregnancies. There was no difference in perinatal outcomes between heterotopic and intrauterine-only pregnancies progressing to live birth.
authors.affiliation: Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA.
authors.forename: Heather B
authors.initials: HB
authors.lastname: Clayton
authors.forename: Laura A
authors.initials: LA
authors.lastname: Schieve
authors.forename: Herbert B
authors.initials: HB
authors.lastname: Peterson
authors.forename: Denise J
authors.initials: DJ
authors.lastname: Jamieson
authors.forename: Meredith A
authors.initials: MA
authors.lastname: Reynolds
authors.forename: Victoria C
authors.initials: VC
authors.lastname: Wright
mesh_terms: D000328:Adult; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000453:epidemiology* / Q000628:therapy*; D008875:Middle Aged; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D018873:Pregnancy Rate; D011271:Pregnancy, Ectopic / Q000453:epidemiology*; D015995:Prevalence; D012042:Registries; D027724:Reproductive Techniques, Assisted; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology