Complete guide on how to take the 1-pill emergency contraceptive for maximum effectiveness.
How do you take the 1-pill emergency contraceptive safely?
To take the 1-pill emergency contraceptive, take it as soon as possible after unprotected or risky sex (best within 24 hours, and no later than 72 hours). If you vomit within 2–3 hours, consider taking another dose. The pill does not protect against your next act of sex — use a condom — and take a pregnancy test if your period is more than 7 days late.
- Take 1 pill as soon as you remember after risky sex (the sooner, the more effective)
- If you vomit within 2–3 hours, consider taking another dose or consult a pharmacist
- Use a condom every time afterward, and avoid further unprotected sex
- If your period is more than 7 days late, take a pregnancy test to be sure
- Do not use it more than twice per menstrual cycle
What's on this page?
- How Many Hours After Sex Should You Take Emergency Contraception? Sooner Is Better
- Emergency Contraceptive Effectiveness by Time Elapsed
- When Should You Use Emergency Contraception?
- Can You Still Get Pregnant After Taking the 1-Pill Emergency Contraceptive?
- How to Take the 1-Pill Emergency Contraceptive Safely and Effectively
- 1-Pill vs 2-Pill Emergency Contraceptive: What's the Difference?
- Side Effects of Emergency Contraception
- Can You Use Emergency Contraception Often?
- Frequently Asked Questions
How Many Hours After Sex Should You Take Emergency Contraception? Sooner Is Better
A condom breaking, forgetting the pill, or having sex without protection — situations like these can happen to anyone, and the first thing many people think of is emergency contraception. But the key question is: how do you go about taking the 1 pill emergency contraceptive correctly and in time?
The short answer is the sooner, the better. The Levonorgestrel 1.5 mg emergency contraceptive commonly used in Thailand is most effective when taken within the first 24 hours, and should not be taken later than 72 hours (3 days) after sex, according to the World Health Organization (WHO)
📖 Read more: If you're looking for a regular contraceptive method that suits you, read Which contraceptive pill brand is best? Comparing popular options in 2026, or if you want to understand the difference between regular and emergency contraception, see Contraceptive pill vs emergency contraception: what's the difference?
Emergency Contraceptive Effectiveness by Time Elapsed
The key principle to remember is that effectiveness drops with every hour that passes. Data from WHO studies and NCBI shows:
| Time Since Intercourse | Approximate Effectiveness | What It Means |
|---|---|---|
| Within 24 hours | 85-95% | Most effective |
| 24-48 hours | 80-85% | Still effective |
| 48-72 hours | 52-75% | Effectiveness drops noticeably |
| After 72 hours | Below 52% | Not recommended, though some sources note limited effect up to 96-120 hours |
⚠️ Important: These figures are study averages. Actual effectiveness may vary by individual, depending on where you are in your cycle and other factors.
When Should You Use Emergency Contraception?
Emergency contraception is meant for urgent situations only — it is not a regular method of birth control. Situations where it should be used include:
- A condom broke or slipped off during sex
- No protection was used at all
- Missed several daily contraceptive pills in a row → read more at What to do if you forget to take the pill
- Miscalculated the safe period
- In cases of sexual assault
Can You Still Get Pregnant After Taking the 1-Pill Emergency Contraceptive?
The honest answer is yes, pregnancy is still possible even after taking emergency contraception, because the pill does not offer 100% protection.
How Does Emergency Contraception Work?
Emergency contraception containing Levonorgestrel works by:
- Delaying or preventing ovulation — if an egg has not yet been released, the pill helps stop that process so there is no egg for sperm to fertilise
- Thickening cervical mucus — making it harder for sperm to pass through
The key thing to understand is that if ovulation has already happened and fertilisation has occurred, emergency contraception will not work. Emergency contraception is not an abortion pill and cannot end an existing pregnancy.
Will Your Period Change After Taking Emergency Contraception?
It is normal for your period to:
- Arrive 1–2 weeks earlier or later than usual
- Come with light spotting
- Be heavier or lighter than usual
🚨 Take a pregnancy test right away if:
- Your period is more than 7 days late
- You have unusually severe lower abdominal pain
- You have abnormal bleeding (which may signal an ectopic pregnancy)
How to Take the 1-Pill Emergency Contraceptive Safely and Effectively
Steps to Take It
- Take 1 pill immediately, as soon as possible after sex (no need to wait or count hours — take it right away)
- Swallow the whole pill with water; do not crush or chew it
- It can be taken before or after food, but if you are prone to nausea, taking it after a meal is recommended
If You Vomit After Taking It
If you vomit within 2 hours of taking the pill:
- You will need to take another pill
- Consult a pharmacist or doctor to confirm
- You may consider taking an anti-nausea medicine before taking the replacement dose
Does Taking More Improve the Effect?
No. Taking extra pills at the same time does not increase effectiveness — it only increases side effects. Take just one full dose (1.5 mg) per act of unprotected sex.
1-Pill vs 2-Pill Emergency Contraceptive: What's the Difference?
| Feature | 1-Pill Version | 2-Pill Version |
|---|---|---|
| Dose | Levonorgestrel 1.5 mg | Levonorgestrel 0.75 mg × 2 |
| How to take | Take 1 pill at once | Take 2 pills together, or 12 hours apart |
| Effectiveness | Equal | Equal |
| Convenience | More convenient — no second dose to remember | Must remember to take the second dose |
According to WHO guidance, both forms are equally effective, but the 1-pill version is more convenient since there's no second dose to worry about.
Side Effects of Emergency Contraception
Most side effects are mild and go away on their own within 1-2 days:
| Symptom | How Common |
|---|---|
| Nausea | 20-50% |
| Vomiting | 10-20% |
| Headache | Common |
| Dizziness / fatigue | Common |
| Breast tenderness | Common |
| Lower abdominal pain / cramping | Common |
| Irregular bleeding | Common |
💡 Tip: If you're worried about nausea, try taking the pill after a meal, or ask a pharmacist about anti-nausea medicine before taking emergency contraception.
Can You Use Emergency Contraception Often?
It's not recommended. Emergency contraception is not designed for regular use and should not be used more than twice per menstrual cycle. Frequent use may cause:
- Irregular periods
- Stronger side effects
- Reduced long-term contraceptive effectiveness
If you find yourself needing emergency contraception often, consider switching to a regular method, such as:
- Monthly contraceptive pills — read more at How to take the contraceptive pill correctly
- Combined hormonal pills — suited to those who also want help with skin and acne; read more at Who is the combined hormonal pill right for?
- Progestogen-only pills — suited to those who are breastfeeding or have restrictions around oestrogen; read more at What is the progestogen-only pill?
- Condoms
- An intrauterine device (IUD)
Frequently Asked Questions
Emergency contraception is not an abortion pill. If you are already pregnant, it has no effect on the existing pregnancy, and current evidence has not found it harmful to the fetus.
Yes. Only a very small amount of Levonorgestrel passes into breast milk (a relative infant dose of about 8%), which is considered safe for infants, according to NCBI
Yes, to some extent. Studies have found that women with a BMI over 30 kg/m² may see reduced effectiveness, but WHO still recommends using it regardless, since it remains better than not using anything at all.
Possibly yes. If you have unprotected sex again after taking emergency contraception, the same pill may not cover that new act, so you should consult a pharmacist or doctor.
No. Emergency contraception only protects against pregnancy — it does not protect against sexually transmitted infections (STIs). You should always use condoms as well.
Alcohol does not directly reduce the pill's effectiveness, but it can increase nausea, and if you vomit within 2 hours you will need to take another dose.
You can start the monthly contraceptive pill as early as the very next day, but you should also use condoms for at least the first 7 days, until the monthly pill reaches full effectiveness.
No. Emergency contraception has no long-term effect on fertility. Your ability to become pregnant returns to normal from the very next cycle.
Emergency contraception can be bought at pharmacies throughout Thailand, or ordered online through Intimo Life after registering as a member and consulting a pharmacist first.
According to IPPF, Levonorgestrel may still have some effect for up to 120 hours (5 days), though effectiveness drops considerably. The UK's FSRH concludes it may not be effective after 96 hours, so you should not rely on it once past 72 hours.
⚠️ Disclaimer
The information on this page is for general informational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment from a qualified doctor or pharmacist. If you have any questions about your symptoms or medication, always consult a doctor or pharmacist first.