How many hours after sex can you use emergency contraception?

There are two main types of emergency contraceptive pill used in the UK, and they have different time limits. Levonorgestrel, which includes the brand Levonelle, needs to be taken within three days, or 72 hours, after sex. Ulipristal acetate, which includes the brand ellaOne, needs to be taken within five days, or 120 hours.

These limits are not a reason to wait until the end of the window. The NHS says the sooner you take an emergency contraceptive pill, the more likely it is to work. How well it works for an individual can depend on factors including how soon it was taken after sex.

Research cited by the NHS suggests that around one to two women in every 100 who take an emergency contraceptive pill will become pregnant. The NHS also says the IUD is the most effective form of emergency contraception. A pharmacist, GP or sexual health clinic can explain the options for your situation.

An IUD can be fitted within five days, or 120 hours, after sex. It is a small, plastic T-shaped device that a specially trained nurse or doctor puts into the womb. The NHS describes the IUD as the most effective type of emergency contraception.

Unlike an emergency contraceptive pill, an IUD needs to be fitted during an appointment, usually at a sexual health clinic or GP surgery. If it is used as emergency contraception, it can also be left in as your usual method of contraception.

The NHS says an IUD can last for five or 10 years depending on the type. Whether it is the right choice in an individual situation is something to discuss with a trained healthcare professional. A GP or sexual health clinic can provide information about fitting and suitability.

Yes. The NHS says the sooner you use emergency contraception, the more effective it usually is. That applies even though the maximum window differs between methods: 72 hours for levonorgestrel and 120 hours for ulipristal acetate or an emergency IUD.

For the emergency pill, the NHS says it is difficult to know exactly how well it will work for a particular person. One of the factors that can affect this is how soon the pill is taken after sex. That is why the maximum time limit should not be understood as a period in which timing makes no difference.

There may also be individual factors that affect which option is suitable. The NHS says the emergency pill may not be suitable if you need to take steroid medicines for asthma or if you are overweight. A doctor, nurse or pharmacist can discuss suitability rather than relying on a general rule.

The NHS advises speaking to a doctor or pharmacist before taking an emergency contraceptive pill if you take certain medicines. These include medicines used to treat TB, epilepsy or HIV, as well as griseofulvin, an antifungal medicine, and St John's wort, a herbal remedy.

In these circumstances, you may be advised to have an IUD fitted as emergency contraception instead. The NHS also says the emergency pill may not be suitable if you need steroid medicines for asthma. A healthcare professional can take your medicines and circumstances into account when discussing the available options.

The NHS says you should generally be able to take the emergency contraceptive pill even if you cannot use some other forms of hormonal contraception, such as the combined pill. It can also be used if you are breastfeeding. For an individual decision, speak to a pharmacist, GP or sexual health clinic.

Feeling sick, or nausea, is one of the common side effects of the emergency contraceptive pill. Period-like pain and cramping are also common. The NHS says the emergency contraceptive pill is very safe and that serious side effects are rare.

If you vomit within two hours of taking an emergency contraceptive pill, you may need another dose as soon as possible. The NHS says you should speak to a pharmacist to find out whether you need another pill.

Because this depends on what has happened after taking the pill, it is important to get advice rather than guessing. A pharmacist can discuss what to do next, and a GP or sexual health clinic can also provide support about emergency contraception and your own circumstances.

Emergency contraception is free from NHS sexual health clinics and GP surgeries. The NHS says you can get the emergency pill or an IUD free from most sexual health clinics, which may also be called family planning or contraception clinics, and from most GP surgeries.

The emergency pill is also available free from some NHS walk-in centres, most pharmacies and some young people's services. You can buy the emergency contraceptive pill from most pharmacies, and many pharmacies also sell it online. The national sexual health helpline number is 0300 123 7123.

Contraception services are free and confidential, including for people under 16. The NHS says a doctor, nurse or pharmacist will not tell anyone, including a parent or carer, unless they think you or someone else is at risk of harm. Emergency contraceptive pills do not protect against sexually transmitted infections. The NHS says using a condom every time you have sex helps protect you and your partner against STIs, including HIV.