Morning After Pill Effectiveness: How Well Does It Work?
Quick Answer
Emergency contraception is highly effective when taken promptly. Postinor is 95% effective within 24 hours (drops to 58% at 72 hours). Mifestad maintains 95%+ effectiveness for 72 hours and still works at 85% up to 5 days. The key factor is timing - take EC as soon as possible for maximum effectiveness.
Effectiveness by Timing
How effective is each EC option? Time is the biggest factor:
| Time After Sex | Postinor | Mifestad |
|---|---|---|
| Within 12 hours | 95%+ | 98%+ |
| 12-24 hours | 95% | 98% |
| 24-48 hours | 85% | 97% |
| 48-72 hours | 58% | 95% |
| 72-120 hours | Not recommended | 85% |
What These Numbers Mean
Understanding effectiveness rates:
When we say Postinor is "95% effective within 24 hours," this means:
- Out of 100 women who would have gotten pregnant without EC
- Only 5 will become pregnant after taking Postinor within 24 hours
- 95 pregnancies were prevented
Important: These rates apply to a single act of unprotected sex. EC doesn't protect against future unprotected sex.
What Affects Effectiveness
Several factors influence how well EC works:
Timing: The most important factor. Take EC as soon as possible.
Body weight: Some studies suggest levonorgestrel (Postinor) may be less effective in women over 70-75kg. Mifestad may be a better option in this case.
Where in your cycle: EC works by preventing ovulation. If ovulation has already occurred, it may be less effective.
Which EC you choose: Mifestad maintains effectiveness longer than Postinor.
What If EC Doesn't Work?
No contraception is 100% effective. If EC doesn't work:
- Track your period: If it's more than a week late, take a pregnancy test.
- EC doesn't harm pregnancy: If you're already pregnant, EC won't affect the pregnancy.
- You have options: If you become pregnant and don't want to continue, speak with a healthcare provider about your choices.
Maximize Your Protection
Pro tips for maximum effectiveness:
1. Take EC immediately - every hour matters
2. If past 48 hours, choose Mifestad over Postinor
3. Don't take multiple doses thinking it works better (it doesn't)
4. Use backup contraception until your next period
5. Consider regular contraception to avoid needing EC
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Order NowFrequently Asked Questions
No contraception is 100% effective. However, EC is highly effective when taken promptly - up to 98% with Mifestad within 24 hours. The key is taking it as soon as possible.
Some research suggests Postinor (levonorgestrel) may be less effective in women over 70-75kg. Mifestad appears to maintain effectiveness regardless of weight. If you're concerned, Mifestad may be the better choice.
No, taking multiple doses doesn't increase effectiveness and may increase side effects. One dose is all that's needed. If you vomit within 2 hours, contact a provider about whether you need a replacement dose.
EC works primarily by delaying ovulation. The longer you wait, the more likely ovulation has already occurred. Once an egg is released, EC can't prevent fertilization.
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