Which emergency contraceptive may be used after unprotected intercourse?

Levonorgestrel is an emergency contraceptive that can be effectively used after unprotected intercourse to reduce the risk of pregnancy. It is most effective when taken as soon as possible within 72 hours after the event, but can still be taken up to five days after unprotected sex, with decreasing efficacy over time. Levonorgestrel works primarily by inhibiting or delaying ovulation, preventing fertilization, and altering the endometrial lining to prevent implantation, if ovulation has already occurred.

Ulipristal acetate, while also an emergency contraceptive, is not the only option available and is usually preferred if it is taken within 120 hours post-intercourse due to its ability to delay ovulation more effectively even closer to ovulation. Estrogen-progesterone combination pills can be used off-label for emergency contraception, but using them specifically for this purpose is less common and involves a different dosing regimen. Mifepristone is primarily used for medical abortion rather than emergency contraception, as it works by blocking the action of progesterone necessary for the continuation of a pregnancy rather than preventing one after intercourse.

Thus, Levonorgestrel stands out as a well-established emergency contraceptive option for use immediately after unprotected intercourse