Emergency contraception (morning after pill)

  • There are no serious side effects of using emergency contraception pills.
  • Reduces risk of pregnancy if you haven't used contraception, or if your contraception has failed.

The emergency contraception (EC) pill (sometimes called the ‘morning after pill’) can be taken after unprotected sex to prevent pregnancy.

There are 2 types of hormonal emergency contraception; one which has to be taken within 3 days of unprotected sex, and the other within 5 days. The non-hormonal coil (IUD) is the most effective emergency contraception if inserted up to 5 days after unprotected sex.

The emergency contraceptive pill is by far the most popular method of emergency contraception, and can be bought without prescription from most pharmacies.

Can be taken
Up to 5 days
Period cycle**
Side effects

*most effective within 24 hours. Effectiveness decreases with time since unprotected sex

**can make earlier or later

How it works

How to use it

For hormonal emergency contraception:

Take one pill, within the specified time period. The emergency contraceptive pill is much more likely to work if you take it within 24 hours of having sex.

There are 2 different types of emergency contraceptive pill:

  • Levonorgestrel (LNG) has to be taken within 72 hours (three days) of sex;
  • Ulipristal acetate (UPA) has to be taken with 120 hours (five days) of sex.

If you’re sick (vomit) within 2 hours of taking Levonorgestrel (LNG), or 3 hours of taking Ulipristal acetate (UPA), seek medical advice as you will need to take another dose or have a non-hormonal coil (IUD) fitted.

You will need to tell the doctor, nurse or pharmacist about the unprotected sex you have had so to they can advise on the most suitable method of emergency contraception.

Why it works

Both types of pill contain ingredients which prevent or delay ovulation (the egg being released from your ovaries). LNG contains levonorgestrel and UPA contains ulipristal acetate.

Things to consider

Emergency contraceptive pills or emergency IUDs do not protect against STIs. You should use condoms to protect yourself from STIs.

STIs can pass from one person to another during sex, especially if you don’t use a condom. It is a good idea to get tested, especially if you have recently changed partners. Most infections can be cured.

Using the emergency contraceptive pill repeatedly can disrupt your natural menstrual cycle.

What if?

You’re already using another form of contraception:

  • Ulipristal acetate (UPA) may prevent other types of hormonal contraception from working for a week after use. You can take it more than once in a menstrual cycle.
  • Levonorgestrel (LNG) does not interfere with your regular method of contraception and you can take it more than once in a menstrual cycle.
  • Levonorgestrel (LNG) and Ulipristal acetate (UPA) do not protect you against pregnancy during the rest of your menstrual cycle and are not intended to be a regular form of contraception.
  • The IUD will not interfere with your regular method of contraception and will continue to give you protection against pregnancy for the rest of the cycle - you can choose to keep it for ongoing contraception.

Emergency contraceptive pills can become less effective at preventing pregnancy if:

  • You are taking other medicines - ask your clinician, GP or pharmacist, and read the information that comes with your medicine.
  • You wait longer than 24 hours to take it (Levonorgestrel (LNG) only).


Most women can take the emergency contraceptive pill. This includes women who cannot usually use hormonal contraception, such as the combined pill and contraceptive patch.

Ulipristal acetate (UPA) is not suitable for women who:

  • are allergic to any of the components of the drug;
  • have severe asthma that is not properly controlled by steroids;
  • have hereditary problems with lactose metabolism.

Side effects & risks


Next period earlier or later than usual.


Can make you feel sick, dizzy or tired, or give you a headache, tender breasts or abdominal pain.

Some women using Ulipristal acetate (UPA) experience painful periods, mood swings, and muscle or back pain.


Does it matter how long I wait to take the emergency contraceptive pill after having unprotected sex?

Yes – Levonorgestrel (LNG) becomes less effective the longer you wait to take it. A trial undertaken by the World Health Organization (WHO) indicated that Levonorgestrel (the drug in LNG) prevented:

  • 95% of expected pregnancies when taken within 24 hours of sex;
  • 85% if taken within 25-48 hours;
  • 58% if taken within 49-72 hours.

What information will I have to give if I want to get emergency contraception?

If you need emergency contraception for recent unprotected sex, you will be asked:

  • when you have had unprotected sex in your current menstrual cycle;
  • the date your last period started;
  • sometimes you'll be asked the usual length of your cycle (from the start of one period to the next);
  • details of any contraceptive failure (such as how many pills you may have missed, and when);
  • if you use medication;
  • your medical history and sexual health history.

How will Ulipristal acetate (UPA) affect my next period?

Your period may come on time or a few days early or late. If your period is over a week late, take a pregnancy test.

When requiring any emergency contraception it is always a good decision to do a pregnancy test 3 weeks after the risk even if a period has come.

What if I take emergency contraceptive pills but my period doesn’t start as usual?

The sooner you take Levonorgestrel (LNG) or Ulipristal acetate (UPA), the more effective it will be.

If your next period is more than 7 days late, or is unusually light or short, contact your GP or Sexual Health Dorset as soon as possible to check for pregnancy.

What if I can’t remember exactly when I had unprotected sex or when my last period was?

If you are unsure about either of these things, and you think you may have had unprotected sex in the last 72 hours, you should take emergency contraception.

Can I get the emergency contraceptive pill in advance?

Ask your GP or nurse if you want to get the emergency contraceptive pill in advance if:

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

Can I take emergency contraception whilst breastfeeding?

Yes, you can take emergency contraceptive pills while breastfeeding. You can also have the IUD fitted while breastfeeding as long as you are more than 28 days post-delivery.

How will the emergency contraceptive pill affect my normal contraception?

The emergency contraceptive pill will not prevent future pregnancies if you have unprotected sex again, so you should make sure you are taking your contraception correctly.

For Levonorgestrel (LNG): If you are using emergency contraception because you forgot your regular pill or did not use the patch or vaginal ring correctly, you should take your regular pill again, insert a new ring or apply a new patch. Use additional contraception, such as condoms:

  • for 7 days with the patch, the ring and the combined pill;
  • for 2 days with the progestogen-only pill.

For Ulipristal acetate (UPA): If you forgot your regular pills, did not use the patch or vaginal ring correctly, or want to start using hormonal contraception, you should wait for 5 days after taking UPA. This is because UPA can reduce the effect of hormonal contraception.

  • use additional contraception, such as condoms;
  • with the patch, the ring and the combined pill, for 7 days (9 days for Qlaira pill);
  • with the progestogen only pill, for 2 days.

How will Levonorgestrel (LNG) affect my next period?

Your period is likely to come on time or a few days early or late. Sometimes it can be a week late and sometimes even later. You may have some irregular bleeding after you take the pill, and before your next period. This can range from spotting to quite heavy bleeding. If your period is over a week late, take a pregnancy test.

What happens if I keep using emergency contraceptive pills?

Ulipristal acetate (UPA) may not be suitable for people who are using proton pump inhibitors such as omeprazole (antacids that regulate their stomach acid levels).

To make an appointment or for further advice, please call:

0300 303 1948

Phoneline open 08:15-16:45 Monday-Friday

(closed 12:30-13:30 for lunch)