Semin Reprod Med 2005; 23: 92-100 DOI: 10.1055/s-2005-864037
Copyright © 2005 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA.
Antiprogestins for Contraception?
Helena von Hertzen1, Paul F. A. Van Look1
1 UNDP/UNFPA/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland

ABSTRACT

Antiprogestins could be a very promising group of compounds for contraception because they counteract the effects of progesterone, a key hormone for normal reproductive functioning. Great efforts have therefore been devoted to testing various ways of using these compounds for family planning. Most of this work has involved mifepristone; other antiprogestins have not been available for trials. With a few exceptions, the outcome of the studies performed to date has not met expectations. The most promising approaches seem to be the use of antiprogestins for emergency contraception, perhaps also as a daily pill when the dose is high enough to block ovulation, and in sequential regimens followed by a progestin. Given that antiprogestins differ in their affinity for target organs, better results could possibly be achieved by using more specific compounds than mifepristone. It is hoped that a wider choice of antiprogestational compounds will soon become available for research.

KEYWORDS

Antiprogestins - mifepristone - contraception - emergency contraception