The Yuzpe regimen is a method of emergency contraception that uses a combination of ethinyl estradiol and levonorgestrel, specifically 1 mg of norgestrel (or 0.50mg of levonorgestrel) and 100 mcg of ethinyl estradiol ASAP and again in 12 hrs.
It is designed to be used within 72 hours of unprotected sexual intercourse because it works by inhibiting ovulation.
[1] Typically, the Yuzpe regimen uses several doses of combined oral contraceptive pills.
[1] 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).
[2] This showed greater efficacy with reduced side effects and has therefore superseded the Yuzpe method.