Low dose mifepristone and two regimens of levonorgestrel for emergency contraception: A WHO multicentre randomised trial

Helena Von Hertzen, Gilda Piaggio, Juhong Ding, Junling Chen, Si Song, György Bártfai, Ernest Ng, Kristina Gemzell-Danielsson, Amindavaa Oyunbileg, Shangchun Wu, Weiyu Cheng, Frank Lüdicke, Alenka Pretnar-Darovec, Rosemary Kirkman, Suneeta Mittal, Archil Khomassuridze, Dan Apter, Alexandre Peregoudov

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Abstract

Background: A single 10 mg dose of mifepristone, and two 0.75 mg doses of levonorgestrel 12 h apart, are effective for emergency contraception. Because no studies had compared the efficacies of both compounds, or investigated a single dose of 1.5 mg levonorgestrel, we undertook this three-arm trial. Methods: We did a randomised, double-blind trial in 15 family-planning clinics in 10 countries. We randomly assigned 4136 healthy women with regular menstrual cycles, who requested emergency contraception within 120 h of one unprotected coitus, to one of three regimens: 10 mg single-dose mifepristone; 1.5 mg single-dose levonorgestrel; or two doses of 0.75 mg levonorgestrel given 12 h apart. The primary outcome was unintended pregnancy; other outcomes were side-effects and timing of next menstruation. Analysis was by intention to treat, but we did exclude some patients from the final analyses. Findings: Of 4071 women with known outcome, pregnancy rates were 1.5% (21/1359) in those given mifepristone, 1.5% (20/1356) in those assigned single-dose levonorgestrel, and 1.8% (24/1356) in women assigned two-dose levonorgestrel. These proportions did not differ significantly (p=0.83). The relative risk of pregnancy for single-dose levonorgestrel compared with two-dose levonorgestrel was 0.83 (95% CI 0.46-1.50), and that for levonorgestrel (the two regimens combined) compared with mifepristone, 1.05 (0.63-1.76). Side-effects were mild and did not differ greatly between groups, and most women menstruated within 2 days of the expected date. Women who took levonorgestrel had earlier menses than did those who took mifepristone. Interpretation: The three regimens studied are very efficacious for emergency contraception and prevent a high proportion of pregnancies if taken within 5 days of unprotected coitus. Mifepristone and levonorgestrel do not differ in efficacy. A 1.5 mg single levonorgestrel dose can substitute two 0.75 mg doses 12 h apart.

Original languageEnglish
Pages (from-to)1803-1810
Number of pages8
JournalLancet
Volume360
Issue number9348
DOIs
Publication statusPublished - Dec 7 2002

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ASJC Scopus subject areas

  • Medicine(all)

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Von Hertzen, H., Piaggio, G., Ding, J., Chen, J., Song, S., Bártfai, G., Ng, E., Gemzell-Danielsson, K., Oyunbileg, A., Wu, S., Cheng, W., Lüdicke, F., Pretnar-Darovec, A., Kirkman, R., Mittal, S., Khomassuridze, A., Apter, D., & Peregoudov, A. (2002). Low dose mifepristone and two regimens of levonorgestrel for emergency contraception: A WHO multicentre randomised trial. Lancet, 360(9348), 1803-1810. https://doi.org/10.1016/S0140-6736(02)11767-3