A progestogen hormone
Levonorgestrel
A progestogen hormone used in the progestogen-only pill, in the hormonal coil (IUS), and as a 'morning-after' emergency contraceptive.
What is Levonorgestrel?
Levonorgestrel is a progestogen, a synthetic version of the hormone progesterone. It is used in progestogen-only contraceptive pills, in the hormonal coil (intrauterine system, or IUS), and as the 'morning-after' emergency contraceptive pill. As emergency contraception the sooner it is taken the better, it is less effective than having a copper coil fitted, and a repeat may be needed if you are sick soon after taking it.
Education and reference only. This is a plain-language guide to Levonorgestrel — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Levonorgestrel is a progestogen, a man-made version of the natural hormone progesterone. It is used in several ways in the UK: in some progestogen-only contraceptive pills, inside a hormonal coil (the intrauterine system, or IUS), and as one of the 'morning-after' emergency contraceptive pills taken after unprotected sex. It is one of the most widely used hormones in contraception.
How it works
As a progestogen, levonorgestrel acts like the body's own progesterone. In day-to-day contraception it mainly thickens the cervical mucus and changes the womb lining so that sperm and a fertilised egg are less able to do their job, and it can also affect ovulation. Used as emergency contraception, it works largely by delaying or preventing the release of an egg (ovulation), which is why timing matters so much.
Company & origin
Originated / developed by: A long-established progestogen.
A widely used progestogen, found in the UK in progestogen-only pills, hormonal coils (the IUS) and the 'morning-after' emergency contraceptive.
Practical use
How to take Levonorgestrel
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- For emergency contraception, take it as soon as possible after unprotected sex — the sooner the better.
- If you are sick within a couple of hours of an emergency dose, contact a pharmacist or GP, as you may need to take it again.
- For the regular progestogen-only pill, take it at around the same time each day as directed.
- Emergency contraception is a backup, not a regular method, so consider ongoing contraception afterwards.
- Ask about the copper coil too, as it is the most effective form of emergency contraception.
Weighing it up
Advantages & disadvantages of Levonorgestrel
Advantages
- Available from pharmacies as emergency contraception, often without a prescription.
- Versatile — used in everyday pills, the long-acting hormonal coil, and emergency contraception.
- The hormonal coil often makes periods lighter and can last for several years.
Disadvantages
- As an emergency pill it is less effective than having a copper coil fitted.
- It works best taken quickly, so any delay reduces how well it works.
- Can cause changes in bleeding, and a repeat may be needed if you are sick soon after taking it.
Practical use
Good to know
As emergency contraception, levonorgestrel works best the sooner it is taken after unprotected sex, so do not delay. It is generally less effective at preventing pregnancy than having a copper coil fitted, which is the most reliable emergency option. If you are sick within a couple of hours of taking the emergency pill, it may not be absorbed and you may need a repeat, so seek advice. It may also work less well if you are above a certain bodyweight or body mass index, in which case a copper coil, a higher dose, or the ulipristal emergency pill (which can be taken a little later in the cycle) may be recommended — ask the pharmacist which is best for you. Used as a regular pill or in the hormonal coil, it can change your bleeding pattern, often making periods lighter or less frequent over time.
Who should not take it / use with caution
- People who have had an allergic reaction to levonorgestrel in the past.
- Those who are already pregnant — emergency contraception will not work and is not used in pregnancy.
- Used with caution alongside certain medicines that can make it less effective, and in some medical conditions — seek advice.
Monitoring
- Whether your next period comes as expected after emergency use — a pregnancy test is advised if it is late.
- Your bleeding pattern when it is used as a regular pill or in the coil.
- Any ongoing need for reliable, regular contraception.
Side effects
- Changes in bleeding, such as spotting, an earlier or later period, or lighter periods with the coil.
- Nausea, tummy ache, headache, breast tenderness or tiredness.
- Being sick soon after an emergency dose may mean it has not been absorbed, so a repeat may be needed.
Key interactions
- Some medicines for epilepsy, certain antibiotics, and St John's wort can reduce how well it works, sometimes needing a different approach.
- Tell the pharmacist or prescriber about all your medicines before taking emergency contraception.
- If you take liver-enzyme-inducing medicines (such as some epilepsy treatments, certain tuberculosis antibiotics, or St John's wort), a copper coil is the most effective option; if that is declined, a higher (double) dose of the levonorgestrel emergency pill may be advised, though it is less certain to work.
Available as: Tablets, including an emergency contraceptive pill, and a hormonal coil (intrauterine system).
Answers
Levonorgestrel: frequently asked questions
How quickly should I take the morning-after pill?
As soon as you can after unprotected sex — the sooner the better, as it becomes less effective with time. It can still be taken up to a few days afterwards, but do not delay.
Is it as good as the coil for emergency contraception?
No. Having a copper coil fitted is the most effective form of emergency contraception. A pharmacist or sexual health clinic can talk you through both options.
What if I'm sick after taking it?
If you vomit within a couple of hours of an emergency dose, it may not have been absorbed and you may need to take it again. Contact a pharmacist or GP for advice.
Can I use it as my regular contraception?
The emergency pill is a backup, not a regular method. Levonorgestrel is also found in everyday progestogen-only pills and the hormonal coil, which your prescriber can discuss.
Will it affect my next period?
It can. Your next period might come a little earlier or later than usual. If it is more than a few days late, take a pregnancy test.
The wider class
About Progestogens / emergency contraception
Levonorgestrel belongs to the progestogens / emergency contraception class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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