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The contraceptive coil

An intra-uterine device (IUD) or intra-uterine system (IUS) are two different types of contraceptive coils (sometimes known simply as a coil). They are both very effective at preventing pregnancy.  

A contraceptive coil is a small device that is inserted into the womb. An IUD will work for 5 to 10 years, and an IUS works for 3 to 5 years, so you don’t need to remember to do anything else to prevent pregnancy during this time. 

A coil does not protect against HIV or other sexually transmitted infections (STIs). So even if you decide to use one you should use condoms as well.  

What is a contraceptive coil?

A small, T-shaped device. It has two thin threads that hang down from your womb into the top of your vagina. 

Although an IUD and an IUS look similar, they are made out of different things. The IUD is made out of plastic and copper (which is why some people call it a copper coil or a copper IUD). An IUS does not have copper in it. It contains the hormone progestogen instead. 

Where can I get a contraceptive coil?

A trained healthcare professional will fit your coil, normally at a sexual health clinic or your local health clinic. 

How do contraceptive coils work?

The IUD releases copper into the womb, while an IUS releases progestogen. Both these things change the mucus inside the cervix (the womb’s entrance), which makes it harder for sperm to reach an egg and survive. It also stops a fertilised egg from implanting itself in the womb and growing. 

The coil is fitted by gently putting a smooth, tube-shaped tool (a speculum) into your vagina so that it can go into your womb. Fitting it should take around five minutes, and you are likely to be tested for STIs beforehand. 

The healthcare professional who fits your coil will show you how to find the threads so you can check each month that it is still in place. 

What are the advantages and disadvantages of using a contraceptive coil?


IUD and IUS:

  • you do not have to think about birth control, so you are in control of whether you get pregnant or not 

  • it is safe to use and can be removed if you have side effects 

  • you can have it taken out at any time, and your natural fertility (ability to have a baby) will quickly return

  • you can use it no matter what other medication you are taking, including HIV treatment   

  • you can get a coil fitted four weeks after giving birth, and it’s safe to use if you’re breastfeeding  

IUD only:

IUS only:

  • it works for three to five years, depending on the brand

  • you can get one at any point in your menstrual cycle. It'll work straight away if it's fitted in the first seven days of your cycle, but if it's fitted at any other time during your cycle you'll need to use other contraception for seven days afterwards.

  • it may be a good option if you cannot take the hormone oestrogen, which is used in the combined contraceptive pill

  • it can make your periods less heavy and painful, and after a year they might stop completely 


IUD and IUS:

  • having a coil fitted can be uncomfortable and even painful. You can have a local anaesthetic (numbing medication) to help if so  

  • a coil doesn’t protect you or your partner from STIs, including HIV – only condoms prevent pregnancy and STIs 

  • it's very unlikely that your coil will come out, but if you cannot feel the threads or think it has moved, you may not be protected against pregnancy 


  • your periods might become heavier, longer or more painful. This is likely to improve after a few months


  • you might get headaches, mood swings, spots or breast tenderness. But these side effects usually go after a few months

How often do I need to get a contraceptive coil?

Every 5 to 10 years for the IUD. Every three to five years for the IUS.

What do I do if forget to replace my coil?

You should go to your doctor. You might also consider taking emergency contraception.

You should also use condoms if you have sex, at least until you get a new coil or swap to a different contraceptive method. 

Do I still need to use condoms if I’m using a contraceptive coil?

Condoms are the only type of contraceptive that protect you and your partner from HIV and STIs, so it is worth using them even if you have a contraceptive coil. 

Will using a contraceptive coil harm my chances of getting pregnant later on?

No. Once a coil is removed, you’ll be able to get pregnant straight away. 

Let's talk about the contraceptive IUD!

Here are a few questions to help kick-off discussions on the issues you need to talk about! You can share them on social, on WhatsApp or just get talking.

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Looking for more detailed information?

Can contraceptive coils tear the womb?

This is very unlikely to happen, it only happens in rare cases. And if a tear does happen it won’t cause any lasting harm. 

Can a contraceptive coil get lost in my body?

On very rare occasions a contraceptive coil can work its way down through the cervix. This means it won’t be effective at preventing pregnancy but it’s not dangerous.  

Can I only have a contraceptive coil if I've already given birth?

No, anyone with a womb can use a coil, whether you’ve had children or not. 

Can a contraceptive coil cause a pelvis infection?

Yes – but only if you have an STI. If you have an undiagnosed STI when you have an IUD or IUS fitted, it increases your risk of getting a pelvis infection during the first 20 days of having the coil. After this, your risk is the same as anyone else’s. If you think you might be at risk of STIs, it’s a good idea to use condoms as well, or consider using a different type of contraception. 

If you have a contraceptive coil and are worried about side effects, talk to your healthcare professional as there are plenty of other birth control methods you can try. 

What advice can I give to someone about contraceptive coils?

The best thing you can do is to give them clear and accurate information, respect their decisions, be open and do not judge. 

They might feel embarrassed about discussing sex with you. If they are, connect them with a friendly healthcare professional, a helpline or factual online resources, like this website. 

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  • Last updated: 24 March 2023
  • Last full review: 01 March 2022
  • Next full review: 01 March 2025
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