Variations on a theme by Yuzpe.

While the Yuzpe regimen of emergency contraception--calling for two doses of oral contraceptives containing ethinyl estradiol and levonorgestrel--remains the standard, different formulations and ways of taking pills after unprotected sex may be equally effective in preventing pregnancy. In a study involving almost 2,000 women attending clinics in the United States and the United Kingdom, those who took two doses of pills containing the progestin norethindrone instead of levonorgestrel and those who took just one dose of the standard Yuzpe regimen had no higher pregnancy rate than those who followed the standard two-dose protocol. (1) Women taking a single dose of pills reported less vomiting than others; otherwise, side effects were similar in all three groups. In a related study conducted in the same clinics, pregnancy rates among 111 women who began the two-dose Yuzpe regimen 4-5 days after having unprotected intercourse were statistically indistinguishable from those among 675 women who initiated treatment within the standard 72 hours. (2) Together, according to the investigators, the studies suggest that when pills containing levonorgestrel are not available, other preparations should be offered, and that the 72-hour cutoff for beginning treatment may be needlessly restrictive.

(1.) Ellertson C et al., Modifying the Yuzpe regimen of emergency contraception: a multicenter randomized controlled trial, Obstetrics & Gynecology, 2003, 101(6):1160-1167.

(2.) Ellertson C et al., Extending the time limit for starting the Yuzpe regimen of emergency contraception to 120 hours, Obstetrics & Gynecology, 2003, 101(6): 1168-1171.