title: Differences between emergency contraception users in the United States and the United Kingdom.
abstract: OBJECTIVE
  to characterize emergency contraception (EC) users and clinical trial participants in the United States and the United Kingdom, comparing previous EC use and awareness, contraceptive history, and experience with EC.
  
  
  METHODS
  We collected data from all EC seekers (n=5383) at 1 US and 2 UK clinics (9/97-8/98). We also collected detailed information from women (n=2157) enrolling in an EC trial at the first 3 clinics and 2 additional UK sites (9/97-2/00).
  
  
  RESULTS
  More US (16%) than UK (4%) women reported additional acts (other than in the last 5 days) of unprotected sex during the cycle in which they sought EC. Fifty-eight percent of UK trial participants had used EC previously compared to 18% in the United States. Most participants in both groups used contraception regularly and reported needing EC because of condom breaks (67% and 56%). More UK than US participants used an ongoing method of contraception (38% v 28%). US women reported more side effects at follow-up than UK women did (76% v 59%), although similar proportions would take EC again or recommend it.
  
  
  CONCLUSIONS
  US and UK women in our trial experienced different side effects. Researchers should use caution when presenting aggregate results from international multicenter trials. In addition, readers should be aware that such aggregate results might mask important geographical differences. More research on experience with EC and barriers to contraceptive use in the United States is needed.
authors.affiliation: Population Council in Johannesburg, South Africa.
authors.forename: Kelly
authors.initials: K
authors.lastname: Blanchard
authors.forename: Sue
authors.initials: S
authors.lastname: Haskell
authors.forename: Sue
authors.initials: S
authors.lastname: Ferden
authors.forename: Karen
authors.initials: K
authors.lastname: Johnstone
authors.forename: Aileen
authors.initials: A
authors.lastname: Spears
authors.forename: Margaret
authors.initials: M
authors.lastname: Evans
authors.forename: Clare
authors.initials: C
authors.lastname: Leadbetter
authors.forename: Sarah
authors.initials: S
authors.lastname: Carlson
authors.forename: Amy
authors.initials: A
authors.lastname: Meehan
authors.forename: Katrina
authors.initials: K
authors.lastname: Abuabara
authors.forename: Charlotte
authors.initials: C
authors.lastname: Ellertson
mesh_terms: D000293:Adolescent; D000328:Adult; D001294:Attitude to Health; D003268:Contraception Behavior / Q000706:statistics & numerical data; D003282:Contraceptives, Postcoital, Hormonal / Q000008:administration & dosage / Q000009:adverse effects; D018849:Controlled Clinical Trials as Topic; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008875:Middle Aged; D012959:Socioeconomic Factors; D006113:United Kingdom; D014481:United States; D016387:Women's Health
chemical_list: D003282:Contraceptives, Postcoital, Hormonal