Emergency contraceptive pill

Also called the ECP or the “morning after pill”

Key points about the emergency contraceptive pill (ECP)

  • The emergency contraceptive pill (ECP) is a pill that is taken after unprotected sex to prevent pregnancy.
  • It is also called levonorgestrel.
  • Find out how to take it safely and possible side effects. 
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The emergency contraceptive pill (ECP) is used to prevent pregnancy after sex, for example if you have unprotected sex, if your regular method of contraception fails (eg, a burst condom) or you forgot to take your regular contraceptive pill.

The ECP is a high dose of the progestogen hormone called levonorgestrel. You have to take 1 or 2 pills within 72 hours of having sex. The ECP has about 98% success rate for those of average weight when taken within four days of unprotected sex. It may not work for heavier people.

You can buy the ECP from a pharmacist or get it from a Sexual Wellbeing Aotearoa clinic or your healthcare provider on prescription. See below, where can I get the ECP?

The ECP is approved to be taken up to 72 hours after sex (within 3 days). However, for most people it is still effective up to 4 days after sex.

  • If you weigh up to 70kg, take 1 pill within 72 hours of unprotected sex.
  • If you weigh over 70kg, The ECP is not the preferred choice to prevent pregnancy. A copper IUD is most effective. If you want to take the ECP, 2 pills together may be more effective, although there is no proof of this yet.

You may feel sick after taking the ECP so it helps to take it with food. If you vomit within 3 hours of taking your dose you will have to get another.

  • The ECP can be taken at any time in your menstrual cycle. 
  • Swallow the tablet whole with water – do not chew.
  • Don't delay taking the tablet, make sure you take the tablet within 72 hours. The tablet works best the sooner you take it after having unprotected sex.
  • If you are already using a regular method of contraception such as the contraceptive pill, you can continue to take this at your regular times.

The use of the ECP is not advised if you have:

  • a condition that affects your small bowel (such as Crohn’s disease) because the medicine might not be absorbed 
  • severe liver problems
  • a history of ectopic pregnancy (where the baby develops somewhere outside the womb)
  • had a disease called salpingitis (inflammation of the fallopian tubes).

A previous ectopic pregnancy or previous inflammation of the fallopian tubes increase the risk of a new ectopic pregnancy.

The ECP works in a few ways to prevent pregnancy by:

  • Stopping or delaying the release of an egg from your ovaries. 
  • Preventing the sperm from fertilising an egg by changing the way the sperm moves in your body.
  • Delaying ovulation, but there is a risk of pregnancy if you have unprotected sex later in your cycle. It doesn’t work once the egg has been released and fertilised. 

There is no evidence that the ECP will affect the unborn baby if you do become pregnant. It doesn’t harm you or the developing embryo. 

It has a success rate of 98% for those of average weight when taken within 4 days of unprotected sex.

If you weigh more than 70kg

The ECP may not work so well if you weigh more than 70kg, or have a body mass index (BMI) over 26 kg/m2.In this situation, a copper IUD is recommended. If you decide you want to take the ECP, you may be advised to take a double dose – 2 pills together.

If you are taking other medicines

Tell your healthcare provider about any other medicines you are taking including prescribed, over-the-counter, from a supermarket or health food shop.  

Some medicines may prevent the ECP from working well. The ECP may be less suitable for you if you have used any of the following medicines during the last 4 weeks:

  • Medicines to treat epilepsy such as phenytoin, carbamazepine, phenobarbitone.
  • Medicines used to treat tuberculosis such as rifampicin, rifabutin.
  • Treatment for HIV (eg, ritonavir or efavirenz) or Paxlovid for COVID-19
  • A medicine used to treat fungal infections (griseofulvin).
  • Herbal remedies containing St John’s Wort (Hypericum perforatum).

In these situations, a copper IUD is recommended. If you decide you want to take the ECP, talk to your healthcare provider. They may recommend to take a double dose – 2 pills together.

  • A few people have mild side effects like feeling sick (nausea) or vomiting. You can take the ECP with food to lessen the chance of nausea.
  • Some women may notice bleeding or spotting and you may have an early or later start to your next menstrual period.
  • Even if you have a period, it's important to have a pregnancy test 3 to 4 weeks after taking the ECP to make sure you are not pregnant.

To make sure the ECP is right for you, your healthcare provider will usually ask you questions about:

  • your usual means of contraception
  • why you need emergency contraception
  • the number of hours since you last had unprotected sex
  • your period
  • whether you have had a pregnancy test recently
  • existing medical conditions such as unexplained vaginal bleeding or Crohn’s disease
  • other medicines you are taking, including those prescribed or bought over-the-counter, or from a supermarket or health food shop
  • health symptoms such as burning or pain when passing urine, lower abdominal pain, pain during or after sex, unusual vaginal discharge and irregular vaginal bleeding or spotting.

This information helps your healthcare provider decide if this type of emergency contraception is safe and suitable for you.

Note: You can get it from a Sexual Wellbeing clinic or your doctor on prescription. You can have the prescription at home just in case and having the ECP handy means you can take it as soon as you realise there is a problem.

Like all medicines, the ECP can cause side effects, although not everybody gets them.

Very common

  • feeling sick (nausea)
  • some irregular bleeding until your next period
  • lower abdominal pain
  • tiredness
  • headache.


  • Being sick (vomiting). If you vomit within 3 hours of taking the ECP you will have to get another.
  • Your period might be different. Most people will have a normal period at the expected time, but some may have their period later or earlier than normal. You might also have some irregular bleeding or spotting until your next period. If your period is more than 5 days late or is unusually light or unusually heavy, you should contact your doctor as soon as possible.
  • You might have tender breasts, diarrhoea or feel dizzy after taking this medicine.

Very rare

  • There is a very small risk of an ectopic pregnancy (pregnancy outside the uterus) if the ECP fails. This can occur with any pregnancy and can be dangerous. If you have cramping or bleeding, see a doctor or go back to the Sexual Wellbeing clinic.
  • If you think you could be hapū (pregnant), have a pregnancy test three to four weeks after you use the ECP.

Tell your doctor or pharmacist if you notice anything that is making you feel unwell.

Emergency contraceptive pill(external link) Sexual Wellbeing Aotearoa
Emergency contraception(external link) Sexual Wellbeing Aotearoa
Jadelle levonorgestrel implant Bayer New Zealand Limited


  1. Levonorgestrel (contraception, emergency)(external link) New Zealand Formulary

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Credits: Healthify He Puna Waiora editorial team. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

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