| a) If COCs containing 50 mcg
ethinyl estradiol (EE) and 250 mcg levonorgestrel (or 500 mcg norgestrel) are used, two
pills should be taken in each dose. Two doses are taken 12 hours apart. The two doses should total at least 200 mcg of EE and 1.0 mg of
levonorgestrel (or 2.0 mg norgestrel). This is the Yuzpe method, which is the recommended
ECP regimen.
50 mcg EE pills (e.g., Ovral, Feminal) each with 250 mcg
(0.25 mg) levonorgestrel or 500 mcg (0.5 mg) norgestrel:
Number of pills in first dose: 2
Number of pills in second dose (12 hours later): 2 |
a) The Yuzpe method is
recommended because it has been shown to be approximately 75% effective in preventing
pregnancy and because COCs are accessible and safe. The safety and efficacy of alternative
methods is now under investigation.
- Trussell J, Ellertson C, Stewart F.
The effectiveness of the Yuzpe regimen of emergency contraception. Family Planning
Perspectives 1996;28:58-64,87.
- Webb A. How safe is the Yuzpe method
of emergency contraception? Fertility Control Reviews 1995;4(2):16-8.
The effectiveness calculation of 75% is based on the
expected number of pregnancies compared to the observed number of pregnancies. Expected
pregnancies are calculated by matching the cycle day of intercourse with expected cycle
day-specific conception rates. Thus, if 100 women have unprotected intercourse once during
the second or third week of their menstrual cycle, about eight would become pregnant. If
those same 100 women used ECPs, only two would become pregnant (75% reduction).
- Trussell J, Ellertson C, Stewart F.
The effectiveness of the Yuzpe regimen of emergency contraception. Family Planning
Perspectives 1996; 28:58-64,87.
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| b) If pills containing 30 mcg EE
and 150 mcg levonorgestrel (or 300 mcg norgestrel) are used, four tablets should be taken
followed by another four 12 hours later. 30 mcg or
35 mcg EE pills (e.g., Lo-ovral, Lo-feminal) each with 150 mcg (0.15 mg) levonorgestrel or
300 mcg (0.3 mg) norgestrel:
Number of pills in first dose: 4
Number of pills in second dose (12 hours later): 4 |
b) Two doses each consisting of
four 30/150 mcg pills are recommended because each dose at least meets the minimum of the
Yuzpe regimen of 100 mcg of EE and 0.5 mg of levonorgestrel (or 1.0 mg of norgestrel) per
dose. Norgestrel contains two isomers, only one of
which is bioactive (levonorgestrel), thus 0.5 mg levonorgestrel is bioequivalent to 1.0 mg
of norgestrel.
- International Medical Advisory Panel,
IPPF. Statement on emergency contraception. Planned Parenthood in Europe 1995;24(2):5-6.
- Program for Appropriate Technology in
Health. Emergency contraception: a resource manual for providers. Seattle: PATH, 1997.
- Consortium for Emergency
Contraception. Using emergency contraceptive pills (ECPs): a prototype ECP training
curriculum. Welcome, Maryland: The Consortium, 1996.
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