Contraception guide

Emergency contraception (morning after pill, IUD)

Emergency contraception can prevent pregnancy after unprotected sex or if your contraceptive method has failed – for example, a condom has split or you've missed a pill. There are two types: 

  • the emergency contraceptive pill (sometimes called the morning after pill)
  • the IUD (intrauterine device, or coil)

There are two kinds of emergency contraceptive pill. Levonelle has to be taken within 72 hours (three days) of sex, and ellaOne has to be taken within 120 hours (five days) of sex. Both pills work by preventing or delaying ovulation (release of an egg).

The IUD can be inserted into your uterus up to five days after unprotected sex, or up to five days after the earliest time you could have ovulated. It may stop an egg from being fertilised or implanting in your womb.

Emergency contraception does not protect against sexually transmitted infections (STIs).

At a glance: facts about emergency contraception

  • Both types of emergency contraception are effective at preventing pregnancy if they are used soon after unprotected sex. Less than 1% of women who use the IUD get pregnant, whereas pregnancies after the emergency contraceptive pill are not as rare. It’s thought that ellaOne is more effective than Levonelle.
  • The sooner you take Levonelle or ellaOne, the more effective it will be.
  • Levonelle or ellaOne can make you feel sick, dizzy or tired, or give you a headache, tender breasts or abdominal pain.
  • Levonelle or ellaOne can make your period earlier or later than usual.
  • If you’re sick (vomit) within two hours of taking Levonelle, or three hours of taking ellaOne, seek medical advice as you will need to take another dose or have an IUD fitted.
  • If you use the IUD as emergency contraception, it can be left in as your regular contraceptive method.
  • If you use the IUD as a regular method of contraception, it can make your periods longer, heavier or more painful.
  • You may feel some discomfort when the IUD is put in – painkillers can help to relieve this.
  • There are no serious side effects of using emergency contraception.
  • Emergency contraception does not cause an abortion.

The emergency pill

How the emergency pill works

How effective the emergency pill is at preventing pregnancy

How it affects your period 

Who can use the emergency pill 

During breastfeeding

If you're already using the pill, patch, vaginal ring or injection

Side effects of the emergency pill

The emergency pill and other medicines

Can I get the emergency pill in advance?

How the emergency pill works


Levonelle contains levonorgestrel, a synthetic version of the natural hormone progesterone. In a woman’s body, progesterone plays a role in ovulation and preparing the uterus for accepting a fertilised egg.

It’s not known exactly how Levonelle works, but it’s thought to work primarily by preventing or delaying ovulation. It does not interfere with your regular method of contraception.


ellaOne contains ulipristal acetate, which stops progesterone working normally. It prevents pregnancy mainly by preventing or delaying ovulation.`

Levonelle and ellaOne do not continue to protect you against pregnancy. This means that if you have unprotected sex at any time after taking the emergency pill you can become pregnant.

Even if you are starting or continuing another method of hormonal contraception, it may not be effective immediately. You will need to use condoms or avoid sex until the contraception is working effectively.

The time it takes for contraception to become effective depends on the emergency contraceptive pill and the method of hormonal contraception being started. Your doctor or nurse will tell you when you can start hormonal contraception and how long you will need to take additional precautions to prevent an unintended pregnancy.

Levonelle and ellaOne are not intended to be used as a regular form of contraception. However, you can use emergency contraception more than once in a menstrual cycle if necessary.

How effective is the emergency pill at preventing pregnancy?

You can get contraception at:

  • most GP surgeries
  • community contraception clinics
  • some GUM clinics
  • sexual health clinics
  • some young people's services
  • some pharmacies 

Find a clinic near you

It can be difficult to know how many pregnancies the emergency pill prevents, because there is no way to know for sure how many women would have got pregnant if they did not take it.

A study published in 2010 showed that of 1,696 women who received the emergency pill within 72 hours of sex, 37 became pregnant (1,659 did not). Of 203 women who took the emergency pill between 72 and 120 hours after unprotected sex, there were three pregnancies.

Find out more about the research on the effectiveness of both emergency contraception pills.

However, it's important to remember that the sooner you take emergency contraception after sex, the more effective it will be.

How it affects your period

After taking the emergency contraceptive pill, most women will have a normal period at the expected time. However, you may have your period later or earlier than normal.

If your period is more than seven days late, or is unusually light or short, contact your GP as soon as possible to check for pregnancy.

Who can use the emergency pill?

Most women can use the emergency contraceptive pill. This includes women who cannot usually use hormonal contraception, such as the combined pill and contraceptive patch. Girls aged under 16 years old can also use the emergency contraceptive pill.


The WHO does not identify any medical condition that would mean a woman shouldn’t use Levonelle.


The manufacturer of ellaOne advises that it should not be used by women who: 

  • are allergic to any of the components of the drug
  • have severe asthma that is treated with glucocorticoids (steroid) tablets
  • have certain rare hereditary problems with lactose metabolism

ellaOne may not be effective in women who are taking liver enzyme-inducing medication. For more information, read The emergency pill and other medicines.



Levonelle can be taken while breastfeeding. Although small amounts of the hormones contained in the pill may pass into your breast milk, it is not thought to be harmful to your baby.


The safety of ellaOne during breastfeeding is not yet known. The manufacturer recommends that you do not breastfeed for one week after taking this pill.

If you are already using the pill, patch, vaginal ring or contraceptive injection

You may need to take the emergency pill if you:

If you have taken Levonelle, then you should: 

  • take your next contraceptive pill, apply a new patch or insert a new ring within 12 hours of taking the emergency pill

You should then continue taking your regular contraceptive pill as normal.

You will need to use additional contraception, such as condoms, for:

  • the next seven days if you use the patch, ring, combined pill (except Qlaira), implant or injection
  • nine days for the combined pill Qlaira 
  • the next two days if you use the progestogen-only pill

If you have taken ellaOne, you will need to wait at least five days before taking your next contraceptive pill, applying a new patch or inserting a new ring. You should then use additional contraception, such as condoms, while waiting to restart your contraceptive method and then for:

  • the next seven days if you use the patch, ring, combined pill (except Qlaira), implant or injection
  • nine days for the combined pill Qlaira 
  • the next two days if you use the progestogen-only pill

What are the side effects of using the emergency pill?

Taking the emergency contraceptive pill has not been shown to cause any serious or long-term health problems. However, it can sometimes have side effects. Common side effects include: 

  • abdominal (tummy) pain
  • headache
  • irregular menstrual bleeding (spotting or heavy bleeding) before your next period is due
  • feeling sick
  • tiredness

Less common side effects include:

  • breast tenderness
  • dizziness
  • headache
  • vomiting (seek medical advice if you vomit within two hours of taking Levonelle, or three hours of taking ellaOne, as you will need to take another dose or have an IUD fitted)

If you are concerned about any symptoms after taking the emergency contraceptive pill, contact your GP or speak to a nurse at a sexual health clinic. You should talk to a doctor or nurse if: 

  • you think you might be pregnant
  • your next period is more than seven days late
  • your period is shorter or lighter than usual
  • you have any sudden or unusual pain in your lower abdomen (this could be a sign of an ectopic pregnancy, where a fertilised egg implants outside the womb – this is rare but serious, and needs immediate medical attention) 

The emergency pill and other medicines

The emergency contraceptive pill may interact with other medicines. These include: 

  • the herbal medicine St John’s Wort
  • some medicines used to treat epilepsy
  • some medicines used to treat HIV
  • some medicines used to treat tuberculosis (TB)
  • medication such as omeprazole (an antacid) to make your stomach less acidic

ellaOne cannot be used if you are already taking one of these medicines, as it may not be effective.

Levonelle may still be used, but the dose may need to be increased – your doctor or pharmacist can advise on this.

There should be no interaction between the emergency pill and most antibiotics. Two enzyme-inducing antibiotics (called rifampicin and rifabutin), used to treat or prevent meningitis or TB, may affect ellaOne while they’re being taken and for 28 days afterwards.

If you want to check that your medicines are safe to take with the emergency contraceptive pill, ask your GP or a pharmacist. You should also read the patient information leaflet that comes with your medicines. 

Can I get the emergency contraceptive pill in advance?

You may be able to get the emergency contraceptive pill in advance of having unprotected sex if:

  • you are worried about your contraceptive method failing
  • you are going on holiday
  • you cannot get hold of emergency contraception easily

Ask your GP or nurse for further information on getting advance emergency contraception.

The IUD as emergency contraception

An intrauterine device (IUD)

How the IUD works

How effective the IUD is at preventing pregnancy

Who can use the IUD

During pregnancy and breastfeeding

Side effects of using the IUD 

The IUD and other medicines

How the IUD works

The intrauterine device (IUD) is a small, T-shaped contraceptive device made from plastic and copper. It’s inserted into the uterus by a trained health professional. It may prevent an egg from implanting in your womb or being fertilised.

If you’ve had unprotected sex, the IUD can be inserted up to five days afterwards, or up to five days after the earliest time you could have ovulated, to prevent pregnancy. It’s more effective at preventing pregnancy than the emergency pill, and it does not interact with any other medication.

You can also choose to have the IUD left in as an ongoing method of contraception.

How effective is the IUD at preventing pregnancy?

There are several types of IUD. Newer ones have more copper and are more than 99% effective. Fewer than two women in 100 who use a newer IUD over five years will get pregnant. IUDs with less copper in them are less effective than this, but are still effective. The IUD is more effective than the emergency pill at preventing pregnancy after unprotected sex.

Who can use the IUD?

Most women can use an IUD, including women who have never been pregnant and those who are HIV positive. Your GP or clinician will ask about your medical history to check if an IUD is suitable for you.

You should not use an IUD if you have:

  • an untreated STI or a pelvic infection
  • certain abnormalities of the womb or cervix
  • any unexplained bleeding from your vagina – for example, between periods or after sex

Women who have a heart condition should consult their GP or cardiologist before having an IUD fitted.

Pregnancy and breastfeeding

The IUD should not be inserted if there is a risk that you may already be pregnant. The IUD can be used safely if you’re breastfeeding, but the risk of complications during insertion is slightly higher.

What are the side effects of the IUD

Complications after having an IUD fitted are rare, but can include pain, infection, damage to the womb or expulsion (the IUD coming out of your womb). If you use the IUD as an ongoing method of regular contraception, it may make your periods longer, heavier or more painful.

The IUD and other medicines

The emergency IUD will not react with any other medication.

Where can I get emergency contraception?

You can get the emergency contraceptive pill and the IUD for free from:

  • a GP surgery that provides contraception (some GP surgeries may not provide the IUD)
  • a contraception clinic 
  • a sexual health clinic (find sexual health services near you)
  • some genitourinary medicine (GUM) clinics
  • some young people's clinics (call 0300 123 7123)

You can also get the emergency contraceptive pill free from:

  • most pharmacies (find pharmacies near you
  • some NHS walk-in centres and minor injuries units
  • some Accident & Emergency departments

The doctor or nurse you see may ask for the following information:

  • when you have had unprotected sex in your current menstrual cycle
  • the date of the first day of your last period and the usual length of your cycle
  • details of any contraceptive failure (such as how many pills you may have missed, and when)
  • if you've used any medications that may affect your contraception

You can buy the emergency contraceptive pill from most pharmacies if you're aged 16 or over and from some organisations such as bpas or Marie Stopes. The cost varies, but it will be around £30 to £35.

Contraception for the future

If you're not using a regular method of contraception, you might consider doing so in order to lower the risk of unintended pregnancy. Long-acting reversible contraception (LARC) offers the most reliable protection against pregnancy, and you don't have to think about it every day or each time you have sex.

LARC methods are the:



Page last reviewed: 13/01/2015

Next review due: 13/01/2017


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The 4 comments posted are personal views. Any information they give has not been checked and may not be accurate.

snehaji said on 30 November 2015

last week i had an unprotected sex wid my husband. it was second day after my period get over. after 10 hrs i had contraceptive pill. n today after 7 days i am having bleeding n also felt vomitting. so i am confused about my pregnancy. is it effect of contraceptive pill or its a pregnancy

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Shimu said on 27 October 2015

I am 18 years, new married. Can I take IUD?

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Kirsty Haley said on 18 April 2014

The information provided here regarding ellaone and breastfeeding is out of date. The latest information from the manufacturer states;
"If you are breast-feeding - Do not breast-feed your baby for one week after taking ellaOne. During this time, it is recommended to pump and discard your breast milk in order to stimulate and maintain lactation."
I have been prescribed this drug even after asking more than once if it was safe whilst fully breastfeeding my 9wk old daughter and being assured it was, only to later find out in the package information, dated October 2012 (after I'd taken the tablet) that I had to "pump-n-dump" for 36 hours...suffice to say I am completely incensed. I then read more online about the drug and breastfeeding and discovered that in March 2013 they confirmed this drug was in breast milk for 5 days so I should discard my milk for 5 days...then if that wasn't even more distressing to me, a little more digging ( the manufacturer now states 1 week!!! Please don't take this drug if you are breastfeeding - I have been completely let down by all involved in allowing me to access this product.

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Jemmima231 said on 08 January 2014

The information on this website regarding which Chemists provide emergency is out of date. Also the Chemist I visited informed me that pharmacies only provide free emergency contraception to under 25s.

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Find emergency contraception services

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