Contraception: Emergency Contraception

Emergency contraception (often referred to as the 'morning after pill') is used to prevent pregnancy following unprotected sex. It may also be used as a precautionary measure if another form of contraception has failed, eg, if a condom has split. Emergency contraception is estimated to prevent pregnancy in about 85% of cases. The sooner emergency contraception is taken after unprotected sex, the more effective it is.

How does it work?

Two types of emergency contraceptive pill are available. The first contains a high dose of progesterone in the form of levonorgestrel (Levonelle 1500® [Levonelle One Step®], Emerres® or Upostelle®). It does not contain any oestrogen. The second contains an ingredient called ulipristal (EllaOne®), which interferes with the actions of progesterone in the body.

Both types of pill are thought to work by preventing the release of an egg from your ovaries (ovulation). They may also cause changes in the lining of the womb which will stop a fertilised egg from attaching to it. In addition, levonorgestrel is thought to prevent fertilisation of any egg that may have already been released, by altering transport of the sperm and/or egg within the fallopian tubes. Emergency contraception will not work if you are already pregnant.

How is it used?

Levonelle 1500® (Levonelle One Step®), Emerres® and Upostelle® should be taken preferably within 12 hours and no later than 72 hours after unprotected sex. EllaOne® can be taken up to 120 hours after unprotected sex. Nausea and vomiting are fairly common side effects of both pills.

Emergency contraception is supplied in a pack containing one tablet. The tablet should be taken as soon as possible. If you are sick within three hours of taking the tablet, another tablet should be taken immediately. You will need to contact your doctor, pharmacist, nurse or sexual health clinic immediately in order to obtain another tablet. Sometimes an additional medicine to prevent sickness (an anti-emetic) may be prescribed, to be taken together with the tablet. If you are taking any prescribed or complementary medicines, the dose of emergency contraception may need to be increased.

Emergency contraception is available in pharmacies with a prescription (as Levonelle 1500®, Emerres®, Upostelle® or EllaOne®) or over the counter without a prescription (as Levonelle One Step® or EllaOne®).

Levonelle One Step® and EllaOne® are classified as Pharmacy (P) medicines and can be sold to women over the age of 16 years. The pharmacist may ask questions about your periods and when you had unprotected sex. Levonelle 1500®, Emerres® and Upostelle® contain exactly the same ingredients as Levonelle One Step® but they are classified as prescription-only medicines (POMs). Levonelle 1500®, Emerres® and Upostelle® may be obtained from GPs, most genito-urinary medicine (GUM)/sexual health clinics and some hospital accident and emergency departments. Your prescriber will help you decide which of these two types of pill is right for you.

Can emergency contraception fail to work?

Emergency contraception is thought to be effective in about 85% of cases. In the remainder of cases, reasons for failure of the method include:

  • taking the dose too late after unprotected sex (ie, more than 72 hours afterwards for levonorgestrel, or more than 120 hours afterwards for ulipristal)
  • being sick within three hours of a dose (a further dose should be taken if this happens)
  • having unprotected sex again after taking the tablet
  • having already had unprotected sex at another time since the last period.

If emergency contraception fails and a pregnancy happens, you should see your doctor as he or she may want to check that the pregnancy is not ectopic (where the baby develops outside the womb). Levonorgestrel has not been shown to harm the baby or affect the pregnancy in any way. The company that makes EllaOne® is collecting information to determine whether ulipristal has any effect on pregnancy.

Is emergency contraception suitable for everyone?

Most women are able to take the emergency contraceptive pill without any problems. However, in women with certain diseases or conditions, or in women taking certain medicines, emergency contraception may not be suitable. Tell your doctor or pharmacist if you are suffering from any disease or condition, and about any medicines you are taking. Emergency contraception is not suitable for women who are already pregnant.

It is not dangerous to use emergency contraception on more than one occasion, but it is not a method of contraception that should be used on a regular basis. Other contraceptive methods used regularly are more effective.

What will happen after using emergency contraception?

After emergency contraception menstrual periods are usually normal and occur at the expected date, although in some women they may be a few days earlier or later than expected. As mentioned previously, some women may feel sick or actually be sick after taking emergency contraception. Some women may have tender breasts, headaches, lower abdominal (stomach) pain or diarrhoea, or feel dizzy or tired after taking emergency contraception. Other possible side-effects include infections, indigestion, mood changes, muscle spasms and back pain. Usually, these symptoms only last for a few days.

Many doctors will arrange a follow-up appointment to check that the next period has started. If there is any unusual pain or bleeding before this time, or if the period is more than a week or two late, you should see your doctor as soon as possible.

Further information available from:

FPA (Sexual Health Charity)
23-28 Penn Street
London N1 5DL
Tel: 020 7608 5240

Fact sheet provided by MIMS

Date last reviewed: September 2016

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