What Are the Available Post-Coital Contraceptive Options?

Emergency contraception—often referred to as “morning-after contraception”—is a time-sensitive intervention designed to prevent pregnancy after unprotected intercourse or contraceptive failure. It is not an abortion method and does not disrupt an established pregnancy. Several evidence-based options are available, each with distinct mechanisms of action, efficacy windows, and administration protocols.

The most effective option is the copper intrauterine device (IUD), which can be inserted up to five days after unprotected sex. When placed within this timeframe, it reduces the risk of pregnancy by over 99%. Its mechanism involves creating a hostile uterine environment for sperm and ova, thereby preventing fertilization and implantation. Importantly, the copper IUD also provides highly effective long-term contraception once in place.

Oral emergency contraceptive pills (ECPs) are more widely accessible but vary in efficacy based on timing and formulation. Levonorgestrel (1.5 mg single dose or 0.75 mg taken twice 12 hours apart) works primarily by delaying or inhibiting ovulation if administered within 72 hours of intercourse. Its effectiveness declines significantly after this window, especially in individuals with higher body weight.

Ulipristal acetate (30 mg single dose) is a selective progesterone receptor modulator approved for use up to 120 hours (five days) post-intercourse. It is more effective than levonorgestrel beyond 72 hours and maintains consistent efficacy across a broader range of body weights. However, it requires a prescription in many jurisdictions and should not be used by individuals currently taking hormonal contraceptives or those with known contraindications such as severe hepatic impairment.

It is critical to emphasize that emergency contraception does not protect against sexually transmitted infections (STIs). Individuals who have experienced unprotected intercourse should be counseled on STI screening and offered appropriate testing. Additionally, ECPs do not replace routine contraception; clinicians should support patients in selecting and initiating a reliable ongoing method during the same visit whenever possible.