Contraceptive efficacy of low doses of mifepristone.
OBJECTIVE
To determine whether a 5-mg dose of mifepristone is sufficient to prevent pregnancy.


METHODS
Clinical study.


METHODS
Academic research center.


METHODS
Healthy, fertile, sexually active female volunteers.


METHODS
Volunteers received a 5-mg dose of mifepristone once weekly, starting on cycle day 2, for up to 6 months. This was their only contraceptive method.


METHODS
Number of pregnancies.


RESULTS
The treatment resulted in a significant decrease in pregnancy rate without affecting the menstrual cycle or causing disturbing side effects.


CONCLUSIONS
A low dose of mifepristone, which does not inhibit ovulation, reduces fertility significantly by affecting the endometrium. However, the contraceptive effect needs to be improved for the drug to compete with other contraceptive methods.
Marions
L
L
Department of Women's and Children's Health, Karolinska Hospital, Stockholm, Sweden.
Danielsson
K G
KG
Swahn
M L
ML
Bygdeman
M
M
D000328:Adult; D003280:Contraceptives, Oral, Synthetic / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D010064:Embryo Implantation / Q000187:drug effects*; D004717:Endometrium / Q000187:drug effects*; D005260:Female; D006801:Humans; D008597:Menstrual Cycle / Q000187:drug effects; D015735:Mifepristone / Q000627:therapeutic use*; D011247:Pregnancy; D012016:Reference Values; D016896:Treatment Outcome
D003280:Contraceptives, Oral, Synthetic; D015735:Mifepristone