Emergency contraception: options, time limits and how it works
Quick answer
Emergency contraception can prevent pregnancy after sex without contraception or when a method has failed. The copper IUD is the most effective option and can be fitted up to five days afterwards. Emergency pills work best the sooner they are taken: levonorgestrel within 72 hours and ulipristal acetate within 120 hours.
Key points
- The copper IUD is the most effective emergency contraception and can be fitted up to 5 days after unprotected sex.
- The levonorgestrel pill should be taken within 72 hours (3 days); the sooner, the more effective.
- The ulipristal acetate pill can be taken up to 120 hours (5 days) afterwards.
- Emergency contraception is not an abortion pill and does not harm an existing pregnancy.
- It does not protect against sexually transmitted infections, so consider an STI test as well.
When might you need emergency contraception?
Emergency contraception is for situations where pregnancy is possible and regular contraception was not used or may have failed. It is not meant as an ongoing method, but it is safe to use whenever you need it, including more than once.
- Sex without any contraception.
- A condom broke, slipped off or was not used for the whole time.
- Missed or late contraceptive pills, or a late contraceptive injection.
- Vomiting or severe diarrhoea while taking the pill.
- Sexual assault. Seek care urgently; services can also offer PEP, STI testing and support.
Why is the copper IUD the most effective option?
A copper intrauterine device (IUD) is a small device placed in the uterus by a trained clinician. As emergency contraception it prevents more than 99% of pregnancies, making it far more effective than either emergency pill. It can be fitted up to five days after unprotected sex, or in some cases up to five days after the earliest likely date of ovulation.
Its effectiveness is not reduced by body weight or by other medicines, and it can be left in place as ongoing contraception for several years. Fitting requires an appointment at a sexual health clinic, family planning service or some GP surgeries, so contact one quickly. If you cannot get an appointment in time, take an emergency pill first; you can still have an IUD fitted afterwards.
How do emergency contraceptive pills work?
There are two types of emergency contraceptive pill. Both work mainly by delaying or preventing ovulation, so they are less effective if ovulation has already happened.
Some medicines, including certain treatments for epilepsy, HIV and tuberculosis and the herbal remedy St John's wort, can make emergency pills less effective, and higher body weight may also reduce their effect. Tell the pharmacist or clinician about any medicines you take and they will advise on the best option. If you vomit within a few hours of taking a pill, seek advice, as you may need another.
- Levonorgestrel: should be taken within 72 hours (3 days) of unprotected sex. It is more effective the sooner it is taken.
- Ulipristal acetate: can be taken up to 120 hours (5 days) afterwards and studies suggest it is more effective than levonorgestrel.
- A pharmacist or clinician will advise how to restart or continue your regular contraception, because hormonal contraception can interact with ulipristal acetate.
Is emergency contraception the same as an abortion pill?
No. Emergency contraception prevents a pregnancy from starting; it does not end a pregnancy that has already begun. According to the WHO, emergency contraceptive pills do not interrupt an established pregnancy or harm a developing embryo. Medical abortion uses different medicines and is a separate service.
Where can you get emergency contraception?
Emergency pills are available from many pharmacies, sexual health and family planning clinics, GPs and some hospital emergency departments. In the UK, they are free from sexual health clinics, GPs and many pharmacies. In India, levonorgestrel emergency contraceptive pills are available over the counter at pharmacies, and government health facilities can also advise.
Pharmacists in many countries can provide emergency pills without a prescription after a short, confidential conversation. You do not need to explain more than is needed to choose the right option.
What should you do after taking emergency contraception?
Your next period may come earlier or later than usual. Take a pregnancy test if your period is more than about seven days late, is unusually light or short, or if you have not had a period three weeks after the unprotected sex.
Emergency contraception does not protect against sexually transmitted infections. If the sex was with a new partner or without a condom, consider an STI test, and ask about PEP within 72 hours if HIV exposure is possible. It is also a good moment to talk to a clinician about a regular method that suits you.
When to see a doctor
- Seek urgent medical help if you have sudden or severe lower abdominal pain after taking emergency contraception, as this can be a sign of an ectopic pregnancy.
- Get care straight away after a sexual assault, for emergency contraception, PEP, STI testing and support.
- Take a pregnancy test and see a clinician if your period is more than seven days late or unusually light.
- Contact a pharmacist or clinic if you vomit within a few hours of taking an emergency pill.
Frequently asked questions
How long after sex can I take emergency contraception?
The levonorgestrel pill should be taken within 72 hours and the ulipristal acetate pill within 120 hours, but both work best the sooner they are taken. A copper IUD can be fitted up to five days afterwards and is the most effective option. If you are close to these limits, contact a pharmacy or clinic as soon as possible.
Is the morning-after pill an abortion pill?
No. Emergency contraceptive pills mainly work by delaying or preventing ovulation, so a pregnancy does not start. They do not end an existing pregnancy and, according to the WHO, will not harm one if you are already pregnant. Medical abortion uses different medicines and is a completely separate treatment.
Can I use emergency contraception more than once?
Yes. Emergency contraception is safe to use more than once, including within the same menstrual cycle. However, it is less effective than regular contraception and is not designed for ongoing use. If you find you need it often, a clinician can help you find a regular method, such as an implant or IUD, that suits you better.