THE YUZPE REGIMEN OF EMERGENCY CONTRACEPTION - HOW LONG AFTER THE MORNING AFTER

Objective: To determine whether failure of the Yuzpe method of emergen cy contraception (which involves taking a higher than usual dose of or dinary combined oral contraceptives within 72 hours after unprotected intercourse, with a second dose taken 12 hours later) depends on the i nterval between intercourse and treatment. Data Sources: We searched t he literature for studies in which investigators separately reported b oth the number of women treated with the Yuzpe regimen and the resulti ng pregnancies when treatment was started on the first, second, and th ird days after unprotected intercourse. Searches of the electronic dat a bases MEDLINE, POPLINE, EMBASE, and BIOSIS were supplemented by scru tiny of the bibliographies of all papers identified through the electr onic search. Methods of Study Selection: We identified nine published studies that present the number of women treated and outcome of treatm ent by time since unprotected intercourse. We included all nine studie s in our analysis. Tabulation, Integration, and Results: Differences i n failure rates by time of treatment adjusted for study-site effects w ere analyzed using logistic regression. We found no significant differ ences in failure rates when therapy was started on the first, second, or third day after unprotected intercourse. The large sample size ensu red a power of 76% to reject the null hypothesis of equal failure rate s when the odds of failure on the third day are twice those on the fir st and second days. Conclusion: Our results have two clinical implicat ions. First, insistence on taking the first dose as soon as possible m ay be counterproductive in circumstances when taking the second dose 1 2 hours later would be difficult. Second, clinical protocols that deny treatment after 72 hours may be excessively restrictive, particularly if the alternative of emergency insertion of a copper intrauterine de vice is not immediately available or appropriate.