If you (or a family member) has had unprotected sex and are worried about being pregnant, you may want to take an emergency contraceptive pill. This is also called the ‘morning after pill’.
How the emergency contraceptive pill works
The emergency contraceptive pill prevents pregnancy by:
- delaying the release of an egg from your ovary until sperm are no longer active, and
- changing the lining of your uterus so a fertilised egg cannot implant and develop.
The emergency contraceptive pill is very successful at preventing pregnancy (96 to 99%).
When to take the emergency contraceptive pill
The emergency contraceptive pill will be most effective if you take it as soon as possible after unprotected sex. Within 24 hours is best, but it can prevent pregnancy if taken up to 120 hours (5 days) after sex.
The emergency contraceptive pill will not prevent pregnancy if taken any later than 120 hours after unprotected sex.
The World Health Organization (WHO) indicated that levonorgestrel (the drug in Postinor) 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
72 hours is the usual cut off time, but a study in 2010 found the risk of getting pregnant was no different at 72 hours compared with 120 hours, with 2% of women becoming pregnant.
You can take it at any point in your menstrual cycle, including during menstruation (period).
How to get the emergency contraceptive pill
Women of any age can get the emergency contraceptive pill.
- You can get it at a low cost (or possibly free) from your doctor or the Family Planning Association.
- It is also available over the counter at some pharmacies.
Some women feel sick after taking the emergency contraceptive pill.
- It helps to take the pill with food.
- There is medicine that can prevent the nausea. Talk to your doctor or pharmacist.
- If you vomit within three hours of taking the emergency contraceptive pill, you’ll need another pill. Contact your doctor or family planning clinic.
- Talk to your doctor if you have a medical condition or history that means you shouldn’t take oral contraceptives (such as deep vein thrombosis, blood clotting disorder, liver disease).
- You can still take the emergency contraceptive pill if you’re on a course of antibiotics.
Call Healthline 0800 611 116 if you are unsure what you should do.
What happens next
Use a barrier contraceptive (condoms) until your next period.
Your next period will probably come at the expected time, but it may be early or late, and it could be heavier than usual.
If you don’t get your next period, or it is very light, you should have a pregnancy test.
The emergency contraceptive pill and pregnancy/breastfeeding
- Do not take the emergency contraceptive pill if you’ve had a positive pregnancy test.
- The emergency contraceptive pill will not cause an abortion if you are already pregnant.
- If you take the emergency contraceptive pill and still become pregnant, there is no evidence that the baby will be harmed.
- Taking the emergency contraceptive pill won’t affect your chances of getting pregnant in the future.
- The emergency contraceptive pill is generally safe to take while breastfeeding – but check with your doctor if you’re concerned.
If you can’t take the emergency contraceptive pill
Another form of emergency contraception is a copper intrauterine device (IUD). ‘Intrauterine’ means it is put into your uterus. This must be done by a doctor or at a family planning clinic.
The IUD prevents implantation of a possible fertilised egg.
If you’ve had unprotected sex and can’t take the emergency contraceptive pill, talk to your doctor or family planning clinic about the IUD as soon as possible.