The coil – what it is, how it works and symptoms after insertion
- What is the coil?
- How does the coil work?
- How effective is the coil?
- How long does the coil last?
- How do I get the coil fitted?
- Does getting the coil fitted hurt?
- What symptoms can I expect after I’ve had the coil inserted?
- Can coil insertion lead to complications?
- Does the coil stop periods?
- What side effects does the coil cause?
- How do I get the coil removed?
Reviewed by our clinical team
Interested in switching up your contraception but not clear on your options? If you’re looking for something really low maintenance and very effective, the coil could be just right. Read on for our comprehensive guide to this popular form of contraception.
What is the coil?
The copper coil is another name for the intrauterine device, or IUD. There's also the hormonal coil, also known as the intrauterine system, or IUS.
The IUD and the IUS are types of long-lasting, reversible contraception that are inserted into the womb to prevent pregnancy. The difference is that the IUD uses copper as a contraceptive, which is why it’s sometimes called the copper coil, while the IUS uses hormones, which is why it’s sometimes called the hormonal coil.
Both types are small, T-shaped devices small enough to hold in your palm. The copper coil (IUD) is made with plastic and copper, while the hormonal coil (IUS) contains progestogen, a synthetic version of the hormone, progesterone.
In addition to being used for regular contraception, the copper coil can also be used as emergency contraception if fitted within five days of unprotected sex. Find out more about the IUD as emergency contraception.
How does the coil work?
The copper coil works by releasing copper, which is a contraceptive. The copper alters the cervical mucus, which makes it more difficult for sperm to reach an egg and survive. It can also stop a fertilised egg from being able to implant itself.
The IUS works by releasing progestogen, which is a synthetic version of the hormone progesterone and also acts as a contraceptive. It thickens the cervical mucus, which makes it more difficult for sperm to move through the cervix, and thins the lining of the womb so an egg is less likely to be able to implant itself.
For some people, it can also prevent the release of an egg each month (ovulation), but most people continue to ovulate.
How effective is the coil?
Both the IUD/copper coil and the IUS/hormonal coil are over 99% effective at preventing pregnancy when positioned correctly.
How long does the coil last?
- The IUD/copper coil lasts for five to 10 years, depending on the type.
- The IUS/hormonal coil last for three to five years, depending on the type.
How do I get the coil fitted?
A coil is not something you can fit yourself – it has to be inserted by a trained healthcare professional. The good news is, this service is available for free on the NHS. You can get the coil fitted at contraception clinics, sexual health/GUM clinics and GP surgeries.
During the appointment the doctor or nurse will need to look at your vagina and check the size and position of your uterus. Then they’ll hold your vagina open and put the device through your cervix into your womb. Both types of the coil have small threads that hang from the bottom, through the cervix – these are there so you can check the device is still in place.
Does getting the coil fitted hurt?
Getting the IUD or the IUS fitted can be uncomfortable, as the device has to be inserted through the cervix. If you’re worried about the pain beforehand, you can speak to the doctor or nurse about getting a local anaesthetic.
What symptoms can I expect after I’ve had the coil inserted?
After having the coil inserted you might have some cramping similar to period pains, as well as some light bleeding. You should be able to manage any pain by taking over-the-counter painkillers like ibuprofen and paracetamol.
Can coil insertion lead to complications?
In rare cases, having a coil inserted can lead to a pelvic infection or damage to the womb. If you experience any pain or tenderness in your abdomen, you have a fever, your vaginal discharge changes (e.g. it becomes smelly), or you experience any unusual bleeding you should see your GP.
Sometimes, your coil might move or come out altogether from your womb. You may be able to tell that this has happened if you can’t feel the threads that hang from the bottom of the device.
Lastly, there’s a slightly increased risk of ectopic pregnancy with the IUD and IUS – but this can only happen if they fail as contraception, which is very unlikely. An ectopic pregnancy is when a fertilised egg implants itself outside of the womb, typically this is in the fallopian tubes.
Does the coil stop periods?
The IUS/hormonal coil can make your periods a lot lighter, shorter and less painful – for some women, periods stop altogether.
However, the IUD/copper coil can have the opposite effect and make your periods heavier, longer and more painful. This won’t happen for all women, and if it does you may find that your periods improve after a few months.
What side effects does the coil cause?
The main side effect of having the IUD/copper coil fitted is heavier and more painful periods – although this won’t happen for everyone.
However, because the IUS/hormonal coil releases progestogen, it can cause:
- Breast tenderness
- Mood changes
- Ovarian cysts – this is uncommon
- Vaginal bleeding and pain – this is uncommon
How do I get the coil removed?
You can get your coil removed at the same place where you had it inserted (e.g. a contraception clinic or GP surgery). With both the IUD and the IUS, there’s a risk of pregnancy as soon as it’s been removed. This is why the NHS recommends using additional contraception like condoms for seven days before you have it removed.
Once your coil has been removed you can have a new coil put in or switch to a different type of contraception (e.g. the pill) unless you are trying to get pregnant.