Yuzpe regimen

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The Yuzpe Regimen is a method of emergency contraception using a combination of estrogen and progestogen hormones and started within 72 hours of sexual intercourse. It has been superseded by a progestogen-only hormonal regimen.


The method was first developed by Canadian Professor A. Albert Yuzpe as a method of reducing potential unwanted pregnancies, including pregnancy from rape.[1][2] He published the first studies demonstrating the method's safety and efficacy in 1974.[1]


This regimen allows a woman who has had unprotected sex to avoid pregnancy by taking 12 hours apart two sufficient doses of estrogen and progestogen hormones. The sooner this is started, the more effective it is and the effectiveness more than 72 hours after sexual intercourse is greatly reduced.

These hormones are administered as a number of combined oral contraceptive pills (COCPs). Each dose can vary from 2 to 5 pills depending on the brand of medication being used. People concurrently taking certain regular medications (e.g. rifamycin and many anticonvulsant drugs) that enhance the liver's break down of other drugs, must use an even higher hormone dose and may be better advised to use as an alternative the insertion of an IUD.

The standard regime is two tablets each with 50 µg ethinyl estradiol and 250 µg levonorgestrel, to be repeated 12 hours later.

The method is not guaranteed to prevent pregnancy and whilst the hormones may make the subsequent period come a few days early or late, a pregnancy test should be carried out if the period is more than 3 days late. The Yuzpe Regimen does not protect against sexually transmitted diseases.

Subsequently, the World Health Organization (WHO) undertook an investigation into the use of progestogen-only tablets as an Emergency Hormonal Contraceptive (i.e. without any estrogen component). This showed greater efficacy with reduced side effects[2] and has therefore superseded the Yuzpe method. A single dose of 100 mg mifepristone is also more effective than the Yuzpe regime.[3]

Side effects

Some temporary, but usually minor, reactions include:

  • Nausea and/or vomiting
  • Breast tenderness
  • Irregular Bleeding
  • Headache or Dizziness

Should vomiting occur within 3 hours of taking a dose, then insufficient hormones may have been absorbed to provide the full contraceptive cover and an additional dose should be taken. Measures that may help to prevent nausea or vomiting include:

  • Take the pills with food.
  • Take Dramamine or Bonine an hour before taking the pills, if you are especially sensitive to or bothered by nausea—however, this step is not necessary.
  • Schedule your doses so that you take the second dose before bed.


Many common combined oral contraceptive pills could be used for the Yuzpe regimen[3], although their manufacturers did not label the pills for this use. Such off-label use of approved medications is legal and commonplace in American medicine. Further, in February 1997, the FDA declared emergency contraceptive use of certain birth control pills, following the Yuzpe regimen, as safe and effective.

Yuzpe regimen dedicated products (Preven in US and Schering-PC4 in UK) were discontinued following the introduction of progestogen-only ECPs (Plan B in US and Levonelle in UK).


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  2. Yuzpe AA, Smith RP, Rademaker AW (1982). "A multicenter clinical investigation employing ethinyl estradiol combined with dl-norgestrel as postcoital contraceptive agent". Fertil Steril. 37 (4): 508–513. PMID 7040117. <templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  3. Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  1. ^ Yuzpe AA, Thurlow HJ, Ramzy I, Leyshon JI (August 1974). "Post coital contraception—A pilot study". J Reprod Med. 13 (2): 53–8. PMID 4844513. <templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  2. ^ Lua error in Module:Citation/CS1/Identifiers at line 47: attempt to index field 'wikibase' (a nil value).
  3. ^ Princeton University's Emergency Contraception Website (not-2-late.com) list of All information regarding pill brands and dosage was provided by List of oral contraceptives that can be used for emergency contraception in the United States.

External links