Emergency Contraception

Authored by , Reviewed by Dr Jacqueline Payne on | Certified by The Information Standard

If you have unprotected sex but do not wish to become pregnant, you may need emergency contraception. This is the term used for contraception used AFTER you have already had sex. There are several options available.

Emergency contraception describes methods of preventing you becoming pregnant after you have had unprotected vaginal intercourse. There are three types of emergency contraception available to women. These are two types of pill, and the intrauterine contraceptive device (IUCD) - also called the coil. These are available free in the UK from your GP practice, NHS walk-in centres, and and organisations (such as or in the UK) and some pharmacies (pills only).

The IUCD is the most effective form of emergency contraception, so you should always consider this option. This is partly because the emergency contraceptive pills are not effective if taken after ovulation has taken place.

Emergency contraception can be used:

  • If you have had sex without using contraception.
  • If you have had sex, but there was a mistake with contraception. For example, a split condom or if you forgot to take your usual contraceptive pills.

This is a pill that contains levonorgestrel which is a progestogen hormone. There are several different brands available, but they all contain the same dose of levonorgestrel. You can get it free on prescription or you can buy it from pharmacies, without a prescription. The usual dose is one pill which contains 1.5 mg of levonorgestrel. Some women need a higher dose. If you weigh more than 70 kg or your BMI is more than 26, you may need a double dose. Also if you are taking certain other medication you may need a higher dose - for example, women taking certain anti-epilepsy medicines.

When do I take it and how does it work?

Take the pill as soon as possible after unprotected sex. The earlier you take the pill, the more effective it is. It should be taken within 72 hours (three days). It is thought to work mainly by preventing or delaying the release of an egg from your ovary, which normally happens each month (ovulation). It is not thought to cause an abortion, ie it does not have an effect if an embryo has already settled (implanted) into the womb (uterus). It will not be effective if ovulation has already taken place (see below).

How effective is the progestogen pill?

Although emergency contraception is effective, it is not as reliable as regular planned contraception. Therefore, it should only be used in emergencies. The progestogen pill becomes gradually less effective the more time elapses after having unprotected sex. However, there is a good chance of preventing pregnancy if it is taken up to 72 hours after unprotected sex.

It is difficult for scientists to work out exactly how effective it is. This is because after having unprotected sex on one occasion, only a few women would get pregnant. It is difficult to work out which women would not have got pregnant anyway and which pregnancies were actually prevented by taking the emergency progestogen pill. If 1,000 women had unprotected sex once, around 60 to 80 would become pregnant. If all those women had taken the emergency progestogen pill, only around 6 to 26 would have become pregnant. It will, however, depend on when it is taken - both in terms of how long after unprotected sex, and how near the fertile time in the menstrual cycle.

It is sometimes used between 72 and 120 hours after unprotected sex but the chance of it working is much less if it is taken after 72 hours, particularly so after 96 hours (four days).

It is also unlikely to be effective if taken after you ovulate, as it works by delaying ovulation. If you have a regular 28-day cycle, your ovulation is likely to happen around Day 14. (Count from the first day of your last period, and call that Day 1.) Cycles and ovulation can often be unpredictable so this may be hard to work out. If it is likely you have ovulated already, you would be better to use the intrauterine contraceptive device (coil) for emergency contraception.

Are there any side-effects with the emergency progestogen pill?

Side-effects with the emergency progestogen pill are uncommon. However, some women feel sick for about 24 hours after taking the pill. Some women are actually sick (vomit). This may be less likely to happen if the pill is taken with food.

If you vomit within three hours of taking the pill then either:

  • Take another pill as soon as possible. (You may need to get a further prescription, or buy another pill from the pharmacy. You may also wish to get a prescription for some antisickness tablets.)
  • OR an intrauterine device (coil) can be inserted (see below).

Other mild side-effects occur in some women for a short time, such as diarrhoea, dizziness and breast tenderness. There may be some change to your periods in the month after taking the pill. Your period may be early, or late, or you may get some erratic bleeding.

Who should not take the emergency progestogen pill?

Most women are able to take the emergency progestogen pill. However, it is not suitable for all women. For example, women with a rare condition called porphyria should not take it. Also women who have very severe gut disease or a past history of ectopic pregnancy or molar pregnancy may not be able to take it.

Several other medicines can interfere with the emergency progestogen pill, meaning it may not work as effectively. This includes:

Make sure the doctor, nurse or pharmacist prescribing you the emergency contraception pill knows about all the other pills you are taking.

If the pill did not work and you became pregnant, there is no evidence that taking the emergency progestogen pill is harmful to the baby.

Ulipristal acetate is a type of emergency contraceptive pill that was launched in the UK in 2009. There are different brand names. It is taken as one single tablet.

When do I take it and how does it work?

Take the pill as soon as possible after unprotected sex. The earlier you take the pill, the more effective it is. It can be taken up to 120 hours (five days) after having unprotected sex. It is a type of hormone which seems to work by stopping or delaying release of an egg (ovulation).

How effective is ulipristal acetate?

Although emergency contraception can be effective, it is not as reliable as regular planned contraception. Therefore, it should only be used in emergencies. It is most effective if you take the tablet as soon as you can after having unprotected sex. The effectiveness decreases the longer you leave before taking the tablet.

It is difficult for scientists to work out exactly how effective it is. After having unprotected sex on one occasion, only a few women would get pregnant. So it is difficult to work out which women would not have got pregnant anyway and which pregnancies were actually prevented by taking the emergency contraception pill. Overall, if 1,000 women had unprotected sex once, around 60 to 80 would become pregnant. If all those women had taken ulipristal acetate, only around one or two would have become pregnant. It will depend on when in the cycle it was taken, however ... If all 1,000 women had had unprotected sex around ovulation time then many more than one or two would become pregnant.

Ulipristal acetate may be slightly more effective than the progestogen contraceptive pill, particularly when taken between 3-5 days after unprotected sex.

Ulipristal is also unlikely to be effective if taken after ovulation (see above). If this is the case, the intrauterine contraceptive device (IUCD) would be a better option. It is possible that it is less effective if you weigh more than 85 kg or your BMI is more than 30.

Who should not take ulipristal acetate?

You may not be able to take ulipristal acetate if you have severe asthma. You should not breastfeed for one week after taking this tablet. However, you can express and then discard your milk in this week so that you can continue to breastfeed afterwards.

Some other medicines can interfere with ulipristal acetate, making it less effective. If you take one of these pills it may be better to use another form of emergency contraception. Medicines which may interfere with ulipristal acetate include:

  • Contraceptive pills containing progestogens. This includes the progestogen emergency contraceptive pill discussed above, progestogen only pills (POPs) and combined oral contraceptive (COC) pills, patches or rings. This means that ulipristal acetate should not be taken as emergency contraception when needed because you have missed a few days of your normal contraceptive pill. It should also not be taken if you have recently taken the levonorgestrel contraceptive pill in the previous week. Progestogens can make the ulipristal acetate less effective (so you might become pregnant) if taken in the seven days before the ulipristal or the five days after it. For the same reason, you shouldn't start a contraception pill within five days of using ulipristal acetate.
  • Medicines for epilepsy - for example, phenytoin and carbamazepine.
  • Two antibiotics called rifampicin and rifabutin (other antibiotics do not have an effect).
  • An over-the-counter remedy called St John's wort, used for low mood.
  • Some medicines used to treat HIV and AIDS, such as ritonavir.

Always make sure the person prescribing you the emergency contraception pill knows about any other medication you are taking.

Are there any side-effects of ulipristal acetate?

Side-effects with the ulipristal acetate pill are uncommon. These can include headaches, feeling sick, tummy (abdominal) pains, dizziness and muscle pains. After taking it, your periods may be different for the next month. Your period may be earlier than expected, later than expected, or you may have some erratic bleeding.

If you are sick (vomit) within three hours of taking ulipristal acetate then you will need to take another tablet. You will need another prescription for this.

  • If you take them after you have produced an egg (ovulated).
  • If you take the progestogen pill more than 72 hours or the ulipristal acetate pill more than 120 hours after unprotected sex.
  • If you are sick (vomit) within three hours of taking the pill and do not take a repeat dose.
  • If you also had unprotected sex at an earlier time since your last period.
  • If you have unprotected sex again after taking emergency contraception.

The most effective method of emergency contraception is to have an intrauterine contraceptive device (IUCD - often known as a coil) inserted by a doctor or nurse. This can be done up to five days after unprotected sex or up to five days from the earliest possible date you could have ovulated. It has the advantage of providing ongoing contraception and is also more effective than taking hormone tablets. Less than 1 woman in 1000 would get pregnant after having the IUCD inserted for emergency contraception, meaning it is nearly 100% effective.

Most women can use the IUCD. Exceptions include those who have copper allergy, and those who have infections or cancer in their genital areas or womb (uterus).

You may be put off by the idea of having a device inserted, but it is worth considering this option seriously if it is important to you not to become pregnant. It is the most effective type of contraception. It is also likely to be effective in situations where the pills may not work - for example, if taken after you ovulate, if you are on other medication, or whatever you weigh. In addition, you will have ongoing contraception.

See separate leaflet called Intrauterine Contraceptive Device (The Coil) for details.

  • Most women have their next period at about the usual time. Sometimes it is a few days earlier or later than expected. See a doctor or nurse if your next period is more than seven days late or if it is lighter than usual. A pregnancy test may be advised.
  • Your next menstrual cycle may also be shorter or longer than usual.
  • There is still a small risk of pregnancy even if you use an emergency contraceptive correctly.
  • You may wish to have a pregnancy test three weeks after you had unprotected sex to be sure the emergency contraception has worked. This is particularly a good plan if you have gone straight on to start hormone contraception as your normal cycle may have been disrupted.

You may want to discuss your regular contraceptive needs with a doctor or nurse. This may be best in a relaxed follow-up consultation.

See a doctor urgently if you have any lower tummy (abdominal) pain or abnormal bleeding in the 2-6 weeks following use of emergency contraception. These are the main symptoms of an ectopic pregnancy. This is rare, but it is best to be aware of the possibility as it is a serious condition. Also, do a pregnancy test or see a doctor if your next due period is more than seven days late. See your doctor if you have any other concerns or questions.

Further reading and references

  • ; Faculty of Sexual and Reproductive Healthcare (March 2017 - updated May 2017)

  • ; Interventions for emergency contraception. Cochrane Database Syst Rev. 2017 Aug 28:CD001324. doi: 10.1002/14651858.CD001324.pub5.

  • ; Ulipristal acetate: review of the efficacy and safety of a newly approved agent for emergency contraception. Clin Ther. 2012 Jan34(1):24-36. doi: 10.1016/j.clinthera.2011.11.012. Epub 2011 Dec 9.

  • ; NICE Evidence Services (UK access only)

  • ; Faculty of Sexual and Reproductive Healthcare (Apr 2017)

  • ; Faculty of Sexual and Reproductive Healthcare (January 2017)

Hi just wondering if anyone has had the Nova t 380 iud? my doctor just prescribed it when I asked about getting the copper coil but I can't find much about it online apart from the fact it's a 5 year...

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