Plan B emergency contraception should be taken as soon as possible after unprotected sex, ideally within 24 hours. It is most effective when taken quickly, with about 95% effectiveness if taken within 24 hours. However, it can be taken up to 72 hours (3 days) after unprotected sex and still reduce the risk of pregnancy, though effectiveness decreases over time. Some sources mention it might have some effectiveness up to 5 days, but it's generally recommended to take Plan B within the 3-day window for best results.
Key Points on Timing
- Take Plan B immediately after unprotected sex for the best chance of preventing pregnancy.
- It is FDA approved to be used within 72 hours (3 days) after unprotected intercourse.
- Effectiveness diminishes as time passes, so waiting longer reduces its ability to work.
- Plan B works by delaying ovulation, so it must be taken before ovulation has occurred.
- If vomiting occurs within 2 to 3 hours after taking Plan B, consult a healthcare provider about retaking it.
This guidance ensures the highest effectiveness in preventing pregnancy after unprotected sex or contraceptive failure.
