title: [Low doses of mifepristone for emergency contraception].
abstract: OBJECTIVE
  To investigate the efficacy of three different low doses of mifepristone for emergency contraception, the side effects and the influence to the next menstruation.
  
  
  METHODS
  A randomized multicentre trial was conducted in Shanghai. 639 women with regular cycles and history of unprotected intercourse within 120 h of attendance were recruited, and they were randomly assigned to three groups. Group I (n = 214) mifepristone 50 mg was given, group II (n = 214) 25 mg and group III (n = 211) 10 mg.
  
  
  RESULTS
  There were eight pregnancies totally, 2 cases in group I, 1 in group II and 5 in group III. After correction for method failure there was only 1 pregnancy in each group and the contraceptive effectiveness rate were 93.4%, 93.3% and 93.8% respectively. The side effects of mifepristone were slight and tolerable and there was significant difference between the 50 mg group and the lower doses (25 mg and 10 mg) groups (P < 0.05) in women with no complaints. There were about 12%-14% women had a early onset of menses and about 25%-28% had a late one, but no significant differences were found among the 3 groups. The average days of delayed onset of next menstruation were significant longer in group I than that in group III (P < 0.05).
  
  
  CONCLUSIONS
  All the 3 doses of mifepristone could be used as an effective emergency contraception.
authors.affiliation: Shanghai Institute of Family Planning Technical Instruction, International Peace Maternity & Child Health Hospital, Welfare Institute, Shanghai 200030.
authors.forename: L
authors.initials: L
authors.lastname: Cheng
authors.forename: C
authors.initials: C
authors.lastname: Tong
authors.forename: Z
authors.initials: Z
authors.lastname: Xiao
mesh_terms: D000293:Adolescent; D000328:Adult; D003267:Contraception / Q000379:methods*; D003283:Contraceptives, Postcoital, Synthetic / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D015735:Mifepristone / Q000008:administration & dosage* / Q000009:adverse effects; D009325:Nausea / Q000139:chemically induced; D014592:Uterine Hemorrhage / Q000139:chemically induced
chemical_list: D003283:Contraceptives, Postcoital, Synthetic; D015735:Mifepristone