Anticoncepción
Emergency contraception
Revisado: 4 de octubre de 2026
Solo en inglés por ahoraEmergency contraception can prevent pregnancy after sex without contraception or when a method fails. Act as soon as you can: it works better the sooner you use it.
When it can help
Emergency contraception is a way to prevent pregnancy after sex. You might need it if you had sex without contraception, if a condom split or slipped off, if you used your usual method incorrectly, or after sexual assault. The emergency pill works by stopping or delaying the release of an egg. It does not cause an abortion, and it cannot end or harm a pregnancy that has already started.
Your options and time limits
There are two types: a copper IUD (coil) and the emergency contraceptive pill, sometimes called the morning after pill. A doctor or nurse can fit a copper IUD within 5 days (120 hours) after sex. There are two kinds of emergency pill. Levonorgestrel needs to be taken within 3 days (72 hours) after sex. Ulipristal acetate needs to be taken within 5 days (120 hours). Whichever you use, the sooner the better.
Which works best
The copper IUD is the most effective type of emergency contraception. It prevents more than 99% of pregnancies. Emergency pills also work well, but in studies about 1 to 2 in 100 people who took one still got pregnant. Ulipristal acetate can still be used between 3 and 5 days after sex, when levonorgestrel is no longer an option. A doctor, nurse or pharmacist can help you decide which is best for you. If you use hormonal contraception, such as the pill, tell them, because it can affect which emergency pill works best.
What to expect after the pill
Emergency pills are safe for almost everyone. There are no age limits, and no health condition rules them out completely. Side effects can include feeling or being sick, headache, period-like cramps, light irregular bleeding and tiredness. If you are sick within 2 hours of taking an emergency pill, you may need another dose, so speak to a pharmacist straight away.
Getting it and what comes next
Depending on where you live, you can get emergency pills from a pharmacy, a doctor or nurse, or a sexual-health clinic. A copper IUD needs to be fitted by a doctor or nurse, and it can stay in as ongoing contraception for years. Emergency contraception is not meant to be your regular method, so it is worth asking about longer-term options. It does not protect against sexually transmitted infections (STIs), so you may also want an STI test.
Afterwards
Take a pregnancy test if your next period is late. If you are not sure when it is due, take one at least 3 weeks (21 days) after the sex. If you might be pregnant, even without a positive test, contact a doctor or nurse the same day if you have pain low down on one side of your tummy or any bleeding. Get emergency help for sudden, severe tummy pain, pain in the tip of your shoulder, heavy bleeding, or feeling very dizzy or faint. These can be signs of a pregnancy growing outside the womb (ectopic pregnancy). After sexual assault, a sexual-health clinic can also offer care and support.
This is general information. Emergency contraception works best the sooner you use it, so contact a pharmacist, doctor, nurse or sexual-health clinic straight away.