DES still used for emergency contraception in 1995
This article reviews information on currently available postcoital contraceptives, and discusses recent advances in postcoital contraception, mostly notably RU 486.
Postcoital contraceptives, or “morning after pills,” are currently available in the form of high dose estrogens, oral contraceptives, danazol and intrauterine devices. These methods are plagued by high incidences of side effects and less than optimal success rates.
Currently, their primary use in the adolescent age group is for victims of sexual assault, but they may also be used as back-up for consensual unprotected intercourse. RU 486, best known as a first trimester abortifacient, has a number of potential uses, including that of a postcoital contraceptive. Two recently published studies from the UK showed RU 486 to have a very low pregnancy rate and fewer side effects when compared with current methods. RU 486 may someday replace high doses of oral contraceptives as the method of choice for postcoital contraception.
Postcoital contraceptives are available for adolescent use in the US. They include combination oral contraceptives (OCs), high dose estrogens, danazol, and IUDs. Mifepristone (RU-486) is currently not available in the US but is used in France, the UK, and Sweden. Postcoital contraception is especially important for adolescents who have a very high pregnancy rate due to poor contraceptive use. Administration of 2-5 mg ethinyl estradiol (EE) for 5 days beginning within 72 hours of unprotected intercourse yields pregnancy rates ranging from 0-0.92%. EE-related side effects include nausea, vomiting, sore breasts, and irregular menstrual bleeding. DES should not be used, since it is associated with reproductive tract anomalies and vaginal cancers in exposed offspring. Conjugated estrogens have not been used in adolescents for postcoital contraception. The Yuzpe regimen consists of 2 tablets of a combined OC with 200 mg EE and 2 mg dl-norgestrel administered within 72 hours of unprotected intercourse followed by the same dose 12 hours later. Common side effects are nausea and vomiting. Its pregnancy rate is 1.8%. Levonorgestrel-containing OCs can also be used. Administration of 800-1200 mg danazol up to 120 hours after unprotected intercourse protects against pregnancy in about 98% of cases. Copper IUDs have a high efficacy rate when used as postcoital contraception (99.9%), but public opinion, medicolegal considerations, financial costs, and potential for infection impede IUD as a postcoital contraceptive in the US. RU-486 is best known as an abortifacient. It is also a potential postcoital contraceptive. Two UK studies find that RU-486 used as a postcoital contraceptive has a very low pregnancy rate and fewer side effects than the Yuzpe regimen and danazol. It is much more costly than currently used postcoital contraceptives (600 mg of RU-486 cost US$ 68, while Ovral costs US$ 0.48-2.24). Nevertheless, RU-486 may replace the higher doses of OCs as a postcoital contraceptive method.
- Postcoital contraception: present and future options, The Journal of adolescent health : official publication of the Society for Adolescent Medicine, NCBI PubMed PMID: 7742340, 1995 Jan.