Pretreatment of the primigravid uterine cervix with mifepristone 30 h prior to termination of pregnancy: a double blind study.
OBJECTIVE
To determine the effect of the antiprogestogen mifepristone (RU 486) on cervical resistance before first trimester termination of pregnancy.


METHODS
Prospective double blind randomized placebo controlled study.


METHODS
Department of gynaecology in a university teaching hospital, Sheffield.


METHODS
80 Primigravid women greater than 18 years of age, undergoing termination of pregnancy at between 7 and 13 weeks gestation.


METHODS
A single dose of 600 mg of mifepristone or placebo given orally 30 h before termination of pregnancy under general anaesthesia.


METHODS
Cervical resistance to dilatation.


RESULTS
Pretreatment with mifepristone significantly reduced the amount of force required to dilate the cervix to 10 mm. In comparison with placebo, the mean sum of the peak forces obtained with dilators 4 to 10 mm was reduced from 84.3 N (SD 29.7) to 46.0 N (SD 26.7). Two women in the treated group had a cervical resistance of greater than 100 N compared with nine women in the placebo group (RR 0.18, 95% CI 0.04-0.89). The 8 mm dilator could be passed with less than 5 N force in 16 women (43%) in the treated group compared with none in the placebo group. Women in the active treatment group had more preoperative pelvic pain and vaginal bleeding but less postoperative pain.


CONCLUSIONS
Mifepristone significantly reduces cervical resistance in the first trimester of pregnancy and produces minimal side effects.
Cohn
M
M
Department of Obstetrics and Gynaecology, Northern General Hospital, Sheffield.
Stewart
P
P
D000032:Abortion, Therapeutic / Q000379:methods*; D000328:Adult; D002584:Cervix Uteri / Q000187:drug effects*; D004107:Dilatation and Curettage; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D015735:Mifepristone / Q000008:administration & dosage*; D010121:Oxytocin / Q000008:administration & dosage; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011292:Premedication
D015735:Mifepristone; D010121:Oxytocin