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The morning after pill: the facts

The morning after pill: the facts

Sometimes sex can be unpredictable. The heat of passion can lead couples to ‘act’ before they think, and no one can predict the durability of a condom or whether it may break. 

Fortunately, even when traditional forms of contraception such as condoms fail, there are still options available. Most notably, the morning after pill.

What is the morning after pill?

The morning after pill is a way of preventing unwanted pregnancy after unprotected sex. It's the most common form of emergency contraception, and is also known as the emergency contraceptive pill.

There are different types of morning after pills

There are two types of morning after pill available in the UK:

How does the morning after pill prevent pregnancy?

Both the Levonorgestrel and ellaOne morning after pills work by having an effect on ovulation – delaying or preventing the release of an egg. The hormones contained in the pills can also affect the lining of the womb, making it harder for an egg to attach.

When can I use the morning after pill?

Women who have had unprotected sex but do not wish to become pregnant may consider taking the morning after pill. Alternatively, couples who have attempted to protect themselves from pregnancy but experienced a split or faulty condom may also consider this option. 

The name ‘morning after pill’ can lead to some confusion, as neither brand of pill has to literally be taken the morning after unprotected sex to be effective. 

  • Levonorgestrel can be taken up to 72 hours (three days) after unprotected sex and still prevent pregnancy.
  • ellaOne can be taken up to 120 hours (five days) after unprotected sex and remain effective.

However, Levonorgestrel should be taken as soon as possible after unprotected sex. The sooner it's taken, the more likely it is to be effective.

How effective is the morning after pill?

No morning after pill is 100% effective. Research on Levonorgestrel found that:

  • When taken within 24 hours, it is 95% effective
  • When taken within 48 hours, it is 85% effective
  • When taken within 72 hours, it is 58% effective

ellaOne will reduce the risk of pregnancy to 9 in 1000 when taken in the first 24 hours, and then can remain effective for up to five days. If you are unsure which pill to take, you can talk to your GP or pharmacist. 

Vomiting within a few hours of taking either pill could affect its ability to prevent pregnancy, as your body may not absorb the entire dose. If this occurs, you are advised to talk to your GP as you may need to take the pill again. 

Find out more about the effectiveness of the morning after pill here

What are the side effects of the morning after pill?

There are no serious side effects, but some women may experience:

  • Stomach ache
  • Nausea
  • Tiredness
  • Headache
  • Irregular menstrual bleeding

Some women who take Levonorgestrel or ellaOne find that their period comes earlier or later than usual, and if this happens there is normally nothing to worry about. However, if your period is more than seven days late, shorter, heavier or lighter than usual, or you experience any sudden or unusual pain in your lower abdomen, you should see a doctor immediately and take a pregnancy test.

Find out more about side effects of ellaOne here

Does the morning after pill affect fertility?

No, there is no evidence that taking the morning after pill, even multiple times, will affect your fertility in the future or make your infertile.

Does the morning after pill cause an abortion?

No, the morning after pill does not cause any kind of abortion. Morning after pills primarily work by preventing or delaying ovulation and fertilisation in the first place.

Levonorgestrel is a synthetic version of the hormone progesterone, which prevents ovulation, and ellaOne contains ulipristal acetate which stops progesterone working normally, preventing or delaying ovulation. Both pills may also cause changes in the lining of your womb which make it difficult for an egg to implant. 

Does the morning after pill protect against STIs?

No, neither Levonorgestrel nor ellaOne protect against sexually transmitted infections like chlamydia, gonorrhoea and herpes. If you think you may have picked up an STI, you should consider getting tested even if you don’t have any symptoms. Ask your GP or local sexual health clinic about this. 

What other forms of emergency contraception are there?

The emergency coil (IUD) also prevents pregnancy after unprotected sex. It is more effective than the morning after pill (99.9% effective if fitted within five days), but you will have to visit your GP or local family planning clinic to get it fitted.

The IUCD is a T-shaped plastic and copper device which is inserted into the uterus where it works by preventing fertilisation and the egg from implanting in the womb. The IUCD can also be used as a form of long-term contraception. Once inserted, it can be left in place for up to 10 years.

Where can I get the morning after pill?

Your GP or family planning clinic can prescribe the morning after pill, and you can buy Levonorgestrel over the counter at a pharmacy. We also offer both Levonorgestrel and ellaOne through our online service.

Can I get the morning after pill in advance?

It is possible to use our service to get the morning after pill if you think you might have unprotected sex. As it is important to take the morning after pill as soon as possible after unprotected sex, getting the morning after pill in advance can be helpful for preventing pregnancy.

Despite this, you should not rely on the morning after pill as a method of routine contraception.

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Authors and editors

Reviewed and updated by: Our clinical team Date reviewed: 23-08-2023