Postcoital contraception

DES used as an emergency contraception, Denmark, 1983

Abstract

Postcoital contraception (PC) has become more effective in recent years and is recommended for women who have had unprotected coitus between the 8th and 17th days of their cycles. Vaginal douche using a spermicide solution is ineffective as it has resulted in a 37% pregnancy rate.

Estrogens are far more effective: Diethylstilbestrol (DES), taken in doses of 25-50 mg daily for 5 days, e.g., 10 mg of conjugated estrogens 3 times daily, and 2.5 mg ethinyl estradiol 2 times daily for 5 days 24-72 hours after coitus, has resulted in a .5-1.5% pregnancy rate. Side effects, however, include nausea, vomiting, mastalgia, menorrhagia, extrauterine pregnancy, and adenocarcinoma in daughters of DES-treated women.

Gestagens, such as .15-.40 mg of d-norgestrel taken 3 hours after coitus, can be used as a form of planned PC. In an experiment, an estrogen-gestagen preparation consisting of 50 mcg ethinyl estradiol and 500 mcg dl-norgestrel taken 12-72 hours after coitus produced a .9% pregnancy rate in 1300 menstrual cycles with few serious side effects. Copper 7 or copper-T IUDs also prevent the implantation of the fertilized egg, and, when used within 5 days after coitus, produced only 1 pregnancy in 727 cases.

The ideal future PC would be a preparation that inhibits either ovulation or nidation and has limited side effects. Among some promising agents are a luteinizing hormone-releasing factor agonist as well as natural and synthetic prostaglandins; however, until their cardiovascular and gastrointestinal side effects have been ameliorated, their routine use is unlikely.

Sources

  • Postcoital contraception, Ugeskrift for laeger, NCBI PubMed, PMID: 6612804, 1983 Jun 13.
  • Image credit bigbible
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