title: A randomized, double-blind, noninferiority study to compare two regimens of levonorgestrel for emergency contraception in Nigeria.
abstract: BACKGROUND
  Unplanned pregnancies are common in Nigeria. Much of the unplanned pregnancies is due to low contraceptive prevalence and high contraceptive user failure rates. High user failure rates suggest the important role of emergency contraception to prevent unplanned pregnancy.
  
  
  METHODS
  Randomized, controlled, double-blind, multicenter, noninferiority trial comparing efficacy and side effects of two emergency contraceptive regimens up to 5 days after unprotected intercourse among 3022 Nigerian women: levonorgestrel administered in two doses of 0.75 mg given 12 h apart and levonorgestrel administered in a single dose of 1.5 mg.
  
  
  RESULTS
  Efficacy was similar between the treatment groups; post-treatment pregnancy proportions were 0.57% in the two-dose regimen vs. 0.64% in the single-dose regimen (risk difference 0.07% (95% CI -0.50 to 0.64). The majority of women menstruated the first day of expected menses and the groups did not differ regarding reported side effects.
  
  
  CONCLUSIONS
  This study shows the simplified emergency contraceptive regimen of single-dose levonorgestrel is not inferior in efficacy to the two-dose regimen among Nigerian women.
authors.affiliation: Centre for Research in Reproductive Health, Olabisi Onabanjo University Teaching Hospital, Sagamu, Ogun State, Nigeria.
authors.forename: Olukayode A
authors.initials: OA
authors.lastname: Dada
authors.forename: Emily M
authors.initials: EM
authors.lastname: Godfrey
authors.forename: Gilda
authors.initials: G
authors.lastname: Piaggio
authors.forename: Helena
authors.initials: H
authors.lastname: von Hertzen
mesh_terms: D000328:Adult; D044363:Contraception, Postcoital / Q000379:methods*; D003283:Contraceptives, Postcoital, Synthetic / Q000008:administration & dosage*; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D016912:Levonorgestrel / Q000008:administration & dosage*; D016015:Logistic Models; D009549:Nigeria; D011247:Pregnancy; D013997:Time Factors; D055815:Young Adult
chemical_list: D003283:Contraceptives, Postcoital, Synthetic; D016912:Levonorgestrel