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 NowWhat this guide means in practice
Health concerns around emergency contraception usually come from a mix of evidence-based information, anecdotes from friends or family, and content seen online. The goal of a concern-focused guide is to separate signal from noise — to identify which worries are supported by clinical research, which are widely misunderstood, and which should be discussed with a healthcare provider before acting.
Most concerns can be sorted into three categories: questions about how the medication works, questions about safety and side effects, and questions about what to expect in the days and weeks after taking it. Each category has its own evidence base and its own conventional advice, and the answers can change depending on age, medical history, and recent contraceptive use.
Where appropriate, this guide points to follow-up steps — including pregnancy testing, scheduling a clinician consult through Ruth Health, or switching to a more reliable ongoing contraceptive method. Concerns become much easier to manage when there is a clear plan for the next 24, 48, and 72 hours.
Frequently 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.
How Ruth Health supports this decision
Ruth Health was built around the practical realities of emergency contraception in the Philippines. That means treating timing seriously, offering discreet same-day delivery in Metro Manila, and ensuring the right product is dispatched for the patient's situation — including provincial delivery windows where Mifestad's longer effectiveness window matters.
Every order goes through a brief, evidence-based intake. When a clinician should weigh in — for example, when a patient is breastfeeding, on enzyme-inducing medications, or unsure about the time elapsed — that review happens before dispatch. Packaging is unbranded, delivery is tracked, and follow-up support is available through chat for as long as it is helpful.
When the situation has urgent components — severe pain, heavy bleeding, possible sexual assault, or signs of serious health issues — the recommendation is always to seek immediate care at a hospital or clinic, with EC support continuing alongside that care rather than replacing it.
Medical Sources
- WHO Emergency Contraception Fact Sheet
- FDA labeling for levonorgestrel and ulipristal acetate
- ACOG guidance on emergency contraception
- Peer-reviewed studies where noted in Ruth content
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