Postcoital contraception: myth or reality?

摘要: In preparation for a clinical trial of an antiprogesterone molecule as postcoital contraceptive method the authors reviewed available research on effectiveness use high-dose estrogen and combined estrogen-progesterone preparations this purpose. The medical literature period 1971-87 included 5 studies former latter regimens that involved over 500 subjects. each these failure rate was calculated by dividing number observed pregnancies total women enrolled. computed true rates 10 in 2 different ways. First derived from reported divided expected according to Tietzes probability pregnancy. Second Dixons table calculated. Since approach requires data date intercourse resulted pregnancy it could not be applied all studies. efficacy below 1%. However recalculations indicated high 48% (Tietze) or 16% (Dixon). COmbined produce 0.16-5%. Here 4.2-100% 5.9-44% implication is enrolled denominator produces substantially lower than potentially pregnant. Given potential underestimation contraceptives more prospective controlled are urged.