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Dr. Jim Shelton's Pearls "Pearl" for the week of July 21, 2003

Contraceptive Pearl - How long for EC?

Q:How soon after unprotected intercourse should emergency contraception be taken? I thought it was within 72 hours, but my colleague says up to 5 days.

A:Five days. The recommendation has been to start within 72 hours. However, 3 relatively new studies (2 with the Yuzpe and 1 with progestin only) all indicate that effectiveness extends at least for 5 days. In each of the studies, while starting in the first 3 days was more effective, starting on days 4-5 was substantially better than that expected without EC. (See Table Below)

Pregnancy Rate EC Type Days 1-3 Days 4-5 None Yuzpe (2 studies) 0.8-2.5% 1.8-3.6% 8% Progestin-only 1.7% 2.3% 8%

References:

  1. Ellertson C et al. Modifying the Yuzpe regimen of emergency contraception : A multicenter randomized controlled trial. Obstet Gynegol 2003;101:1160-7.
  2. Rodrigues I et al. Effectiveness of emergency contraceptive pills between 72 and 120 hours after unprotected sexual intercourse. Am J Obstet Gynecol 2001;184:531-7.
  3. von Hertzen H et al. Low dose mifepristone and two regimens of levonorgestrel for emergency contraception: A WHO multicentre randomized trial. Lancet 2002;360:1803-10.


The "Pearls" offer answers to commonly asked questions about family planning. These "Pearls" are prepared by Dr. James D. Shelton, Senior Medical Scientist, Office of Population, United States Agency for International Development (USAID)

Disclaimer: The information provided on this web site is not official U.S. Government information and does not represent the views or positions of the U.S. Agency for International Development, the U.S. Government or The Johns Hopkins University.