Plan B (emergency contraception) is highly effective when taken quickly after unprotected sex, with about 95% effectiveness if taken within 24 hours. Since the user asked about effectiveness within 1 hour, it can be understood that Plan B is at its highest effectiveness in that timeframe. This is because the pill works primarily by delaying ovulation, preventing fertilization of an egg. In summary:
- Within 1 hour of unprotected sex, Plan B is approximately 95% effective or possibly slightly higher, given the general data on its efficacy within 24 hours.
- Effectiveness decreases the longer the wait after sex, dropping to around 61% between 48 to 72 hours.
- Plan B cannot reverse ovulation that has already occurred or terminate an established pregnancy, so earlier is always better.
- Effectiveness may be lower in people with higher BMI.
Therefore, taking Plan B within 1 hour of unprotected sex offers one of the best chances to significantly reduce the risk of pregnancy.
