Emergency contraception — your options explained
Reviewed by the My London Pharmacy clinical team, Zeenah Araim, Pharmacist Independent Prescriber
·29 July 2026
·8 min read
Quick answer
Emergency contraception can help prevent pregnancy after unprotected sex or contraceptive failure. In the UK there are two emergency contraceptive pills — one containing ulipristal acetate and one containing levonorgestrel — as well as the copper coil. The sooner it is used, the more effective it tends to be.
How emergency contraception works
Emergency contraception is used to reduce the chance of pregnancy after unprotected sex, a missed pill, or when a barrier method such as a condom fails or slips. It is designed as a safety net for occasions when your usual protection has not worked or was not used, rather than as a method to rely on month after month. Knowing that it exists, and how quickly to act, can take a great deal of worry out of an otherwise anxious situation.
The emergency contraceptive pills work mainly by delaying or preventing ovulation — the release of an egg from the ovary. Sperm can survive inside the body for several days, so if ovulation can be pushed back until after any sperm have died, an egg is far less likely to be fertilised. This is also why timing is so important: once ovulation has already happened in that cycle, the pills have much less opportunity to work. The copper coil works in a different way, by changing the environment within the womb so that fertilisation and implantation are prevented. None of these methods will disturb or end an established pregnancy — if you are already pregnant, they simply will not have an effect.
The two emergency pills
There are two emergency contraceptive pills available in the UK, and although they are often talked about together as the morning-after pill, they contain different active ingredients and have different windows of use. EllaOne 30mg contains ulipristal acetate and can be taken up to 120 hours — five days — after unprotected sex. Levonorgestrel 1500mcg contains levonorgestrel, a synthetic version of a natural hormone, and can be taken up to 72 hours, or three days, afterwards.
Both are taken as a single tablet, swallowed as soon as possible. Ulipristal acetate is generally considered the more effective of the two oral options, particularly in the day or two before ovulation when the risk of pregnancy is highest. However, the more suitable choice depends on your individual circumstances — including how long ago you had unprotected sex, your body weight, any regular medicines you take, and whether you are breastfeeding. Certain medicines and some herbal remedies can reduce how well the pills work, and the two options are not affected in exactly the same way. A pharmacist or clinician can quickly talk this through with you and help you decide which is more appropriate.
Choosing the right option for you
With three options available — two pills and the copper coil — it can help to understand how a clinician weighs them up. The single most important factor is time: how many hours or days have passed since unprotected sex, and where you are likely to be in your menstrual cycle. The closer you are to ovulation, the more the choice matters, because this is when the pills are working hardest against the odds.
Body weight is another consideration, as there is some evidence that the oral options may be less effective at higher weights, and a clinician may suggest EllaOne 30mg or the copper coil in that situation. Your recent contraceptive history also plays a part; for example, if you have recently used a progestogen-based method, this can affect how well ulipristal acetate works. None of this is something you need to work out alone. A short, confidential conversation is enough to match the option to your situation, and there is no wrong door — asking is always the right first step.
The copper coil
The copper intrauterine device (IUD), often called the copper coil, is the most effective form of emergency contraception, and it works regardless of body weight. Fitted by a trained clinician within five days of unprotected sex — or within five days of the earliest point you could have ovulated in your cycle — it prevents the great majority of pregnancies, which is why it is offered as the most reliable choice where it can be arranged in time.
An added advantage is that, once in place, the copper coil can stay on as an ongoing method of contraception for up to five or ten years depending on the device, offering long-term protection without you having to think about it. It does need to be fitted at a clinic, sexual health service or GP practice, and appointments are not always immediate, so it is worth asking early if this is an option you would like to consider. If a coil cannot be arranged within the time window, an emergency pill can often be taken in the meantime.
Timing and effectiveness
With emergency contraception, timing is everything. The emergency pills are more effective the sooner they are taken after unprotected sex, so it makes sense to act rather than wait to see what happens — even if it is the middle of the night or a weekend, the sooner it is taken the better the chance of it working. If you are sick within two or three hours of taking Levonorgestrel 1500mcg, or within three hours of taking EllaOne 30mg, it may not have been fully absorbed, and you should seek advice, as another dose or a different method may be needed.
It is also worth being realistic: no emergency contraceptive pill is 100% effective, and none prevents every pregnancy. This is not a reason to avoid using them, but it is the reason a follow-up pregnancy test is recommended if your next period is more than a week late, is much lighter than usual, or does not arrive as you would expect. If in doubt, a test gives a clear answer and peace of mind, and it can be done discreetly at home.
What to expect afterwards
Most people have no lasting effects after taking emergency contraception. Some notice mild, short-lived side effects such as nausea, headache, tiredness, dizziness or tummy discomfort, and some have tender breasts or a little spotting. These typically settle within a day or two. Your next period may arrive a few days earlier or later than expected, and a change in its timing is common and not usually a cause for concern on its own.
What happens next with your regular contraception depends on which pill you took. If you were already using a hormonal method such as the combined pill or the progestogen-only pill and you take levonorgestrel, you can usually continue it straight away, using extra precautions such as condoms for a period of time. After ulipristal acetate, you may be advised to wait five days before starting or restarting hormonal contraception, because the two can interfere with one another, again using condoms in the meantime. The precise advice varies by method, so it is worth checking with a pharmacist so that you stay protected without a gap.
Where to get emergency contraception
Emergency contraception is widely available in the UK, and there is usually more than one route to it. Community pharmacies can supply the emergency pill after a brief, confidential conversation, and in many areas this is free through NHS arrangements. Sexual health and contraception clinics, GP surgeries and some NHS walk-in services can also provide the pills, and are the usual places to have a copper coil fitted.
Because time affects how well emergency contraception works, it is sensible to choose whichever option you can access soonest rather than waiting for one particular service to become available. If you are travelling, away from your home area, or simply prefer discretion, an online consultation can be a straightforward way to access the emergency pill quickly. Whichever route you choose, the conversation is confidential and non-judgemental, and staff deal with these requests routinely.
Ongoing contraception and support
Emergency contraception is a valuable backup, but a regular method offers far more reliable, ongoing protection and removes the stress of racing against the clock. If you find yourself needing emergency contraception, it can be a useful prompt to review your usual contraception with a clinician and consider an option that fits your routine and your body — whether that is a daily pill, a longer-acting method, or something you do not have to remember at all.
It is also worth remembering that emergency contraception does not protect against sexually transmitted infections, so if there is any chance of exposure, testing is worth considering a couple of weeks later. NHS services, sexual health clinics and pharmacies can all provide emergency contraception and confidential advice, and our clinical team can support you discreetly in understanding your options and choosing what is right for you, both now and going forward.
Frequently asked questions
How soon should I take emergency contraception?
As soon as possible after unprotected sex. Levonorgestrel 1500mcg works within 72 hours and EllaOne 30mg within 120 hours, but effectiveness is higher the sooner it is taken.
Does emergency contraception end an existing pregnancy?
No. Emergency contraception works mainly by delaying ovulation and does not affect or harm an established pregnancy.
Can I use emergency contraception more than once?
Yes, it can be used more than once if needed, including more than once in a cycle, though it is not intended as a regular method. Speak to a clinician about ongoing contraception.
Will it affect my period?
Your next period may be earlier or later than usual and some spotting is common. If your period is more than a week late, take a pregnancy test.
Does it protect against STIs?
No. Emergency contraception does not protect against sexually transmitted infections. Consider testing if there may have been a risk.