Low doses of mifepristone for emergency contraception
Cheng, L.; Tong, C.; Xiao, Z.
Zhonghua Fu Chan Ke Za Zhi 34(6): 335-338
1999
ISSN/ISBN: 0529-567X PMID: 11360608 Document Number: 510770
To investigate the efficacy of three different low doses of mifepristone for emergency contraception, the side effects and the influence to the next menstruation. 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. 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). All the 3 doses of mifepristone could be used as an effective emergency contraception.