Post-coital contraception: an overview of published studies.

Information from published studies testing the effect of hormonal and mechanical interceptive methods in post-coital contraception was pooled with the aim of assessing the efficacy of various regimens. The pooled failure rates were 0.6% (19/3168 based on four studies) for high-dosage ethinylestradiol, 1.1% (11/975, based on two studies) for other high-dose estrogens, 1.8% (69/3802 based on 11 studies) for combined estro-progestin preparations, 2.0% (20/998 based on three studies) for danazol and 0.1% (1/879 based on nine studies) for intra-uterine devices (IUD). Although this overview has several limitations in terms of over-representation of optimistic results in the literature or absence of direct comparison between treatments in several studies, it suggests that IUD and high-dose ethinylestradiol are more efficacious forms of post-coital contraception than danazol or combined contraceptives.