The Hard Truth: Plan B's Time Limit
Plan B One-Step and its generic counterparts contain levonorgestrel, an emergency contraceptive primarily preventing pregnancy by delaying or preventing ovulation. Timing is critical for its success; Plan B is most effective within 72 hours (3 days) of unprotected intercourse. While some sources mention lesser effectiveness up to 5 days (120 hours), it's generally considered ineffective after this period.
The time limit is due to its mechanism: Plan B stops egg release (ovulation). If ovulation has already occurred, it won't prevent pregnancy. Sperm can live for up to five days in the reproductive tract. After this window, levonorgestrel cannot prevent conception. After 7 days, preventing ovulation is impossible, and a fertilized egg may have already implanted, which Plan B cannot stop.
What are your options after 7 days?
Since Plan B is ineffective after 7 days, consider alternative emergency contraception methods effective within a specific timeframe. The best option depends on days passed and individual weight.
The Copper IUD
The copper intrauterine device (IUD) is the most effective emergency contraception. Inserted by a healthcare provider within five days of unprotected sex, it's over 99.9% effective. It works regardless of body weight or menstrual cycle timing by creating a toxic environment for sperm and eggs, preventing fertilization and implantation. The copper IUD can remain for up to 10 years for long-term contraception. However, the 5-day insertion window means it's not an option after 7 days.
The Prescription Pill: ella
Ella (ulipristal acetate), another oral emergency contraceptive requiring a prescription, is effective for up to 120 hours (5 days) after unprotected sex. Unlike Plan B, ella maintains effectiveness throughout the 5-day period and is more effective for individuals over 165 pounds. After 7 days, ella is also not a suitable option, and a pregnancy test is recommended if a period is missed.
When to take a pregnancy test
If 7 days have passed, the next step is typically to wait and take a pregnancy test. Pregnancy tests detect hCG, a hormone produced after implantation. For accuracy, wait at least two weeks after unprotected sex or if your period is more than a week late. Testing too early can result in a false negative.
Choosing an emergency contraception method
Choosing emergency contraception requires quick action and considering time elapsed, body weight, and access to a healthcare provider. The table below compares common options:
| Feature | Plan B (Levonorgestrel) | Ella (Ulipristal Acetate) | Copper IUD |
|---|---|---|---|
| Availability | Over-the-counter (OTC) | Prescription only | Requires healthcare provider insertion |
| Time Window | Most effective within 72 hours; up to 120 hours (less effective) | Up to 120 hours (5 days) | Up to 120 hours (5 days) |
| Effectiveness | 75-89% effective within 72 hours; decreases after | 85% effective throughout 5-day window | >99.9% effective |
| Weight Consideration | May be less effective for individuals over 165 lbs | May be less effective for individuals over 195 lbs | No effect from body weight |
| Mechanism | Delays or prevents ovulation | Delays or prevents ovulation | Creates toxic environment for sperm and egg |
| Bonus Feature | No prescription needed, readily available | More effective for heavier individuals and later use | Can serve as long-term contraception |
Emergency contraception is not an abortion pill
Emergency contraception is designed to prevent pregnancy, not terminate an existing one. If implantation has occurred, these methods are ineffective. Understanding the difference between emergency contraception and a medication abortion pill is important for sexual health.
Conclusion
To reiterate, Plan B will not work after 7 days as its effectiveness window is limited to the first 5 days, peaking within 72 hours. After 7 days, you are beyond the timeframe for any oral emergency contraceptive. If you miss your period, take a pregnancy test. Emergency contraception is not a substitute for regular birth control. If you are within the 5-day window, understand the differences between Plan B, ella, and the copper IUD to make an informed choice. Consult a healthcare professional for personalized advice. Act quickly if you need emergency contraception.
What to do next
If more than 5 days have passed and you are concerned about pregnancy, wait for your next period. If it's delayed by more than a week or you have pregnancy symptoms, take a pregnancy test. Discuss long-term birth control with a healthcare provider. The copper IUD, the most effective emergency option, can also be a reliable long-term contraceptive. For more information, visit Planned Parenthood or consult your doctor.
