Everything you need to know about the contraceptive coil

Reviewed by Dr Bhavini Shah

Interested in switching up your contraception but not sure on your options? If you’re looking for something low maintenance and effective, the coil could be right for you.

In this article we’ll look in depth at what the coil (IUD/IUS) is, how it works and side effects some women might experience after getting the coil inserted.

What is an IUD?

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-acting, reversible contraception that are inserted into the womb to prevent pregnancy. The difference is:

• The IUD uses copper as a contraceptive, which is why it’s sometimes called the copper coil
• 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 non-hormonal, it’s made with plastic and copper. 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 an IUD work?

The copper coil works by releasing copper. The copper in the IUD stops sperm and eggs from surviving. It also changes your cervical mucus to stop sperm from reaching an egg.

An IUD may also work by stopping a fertilised egg from implanting in the uterus.

The IUS works by releasing progestogen, which is a synthetic version of the hormone progesterone and 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 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 effective is an IUD?

The IUD is 99% effective at stopping you from getting pregnant. If it has been inserted properly by a healthcare professional and is still in place.

It is unlikely that your IUD will come out, but it is advised that you check that it is in place often. You can do this by feeling the two thin threads that hang down from your womb into the top of your vagina.

Having an IUD fitted will not protect you from catching an STI. You’ll also need to use a barrier method such as condoms during sex. 

How to get an IUD fitted

A coil is not something you can fit yourself – it must be inserted by a trained healthcare professional. This service is available for free on the NHS. You can get the coil fitted at contraception clinics, sexual health/GUM clinics and some GP surgeries.

They will ask you some questions about your health and then will do an internal examination to check the size and position of your uterus. Sometimes they will also check for any STIs. 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.

“I’d recommend taking some painkillers an hour before your appointment. You may feel pain/discomfort but this shouldn't last long. If you’re particularly concerned about pain during the fitting, speak to the nurse or doctor. They may be able to offer you extra pain relief. For example, you may be offered a local anaesthetic.” - Dr Bhavini Shah 

Does an IUD hurt?

Getting the IUD or IUS fitted can be uncomfortable, as the device must 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 to expect after having an IUD

After having the coil inserted you might have:

• Some cramping similar to period pains
• Some light bleeding 

You should be able to manage any pain by taking over-the-counter painkillers like ibuprofen and paracetamol.

If you have pain in your lower tummy, a high temperature and smelly discharge speak to the healthcare team who inserted your IUD.

Who can have an IUD?

Most women can have an IUD fitted, even if you have HIV. A GP or nurse will be able to check your suitability during an appointment at your local doctor’s surgery or sexual health clinic.

An IUD may not be suitable for you if:

• You think you might be pregnant
• You have an untreated pelvic infection or STI
• You experience problems with your womb or cervix
• You have unexplained bleeding after sex or between your periods 

Potential side effects of an IUD

Not everyone experiences side effects after having the IUD/copper coil fitted. However, side effects include:

• Heavier periods
• More painful periods
• Thrush
• Period-like pain
• Bleeding between periods 

The IUS/hormonal coil releases progestogen, it can cause side effects like:

• Period-like pain and bleeding after an IUS is fitted
• Acne 
• Breast tenderness 
• Mood changes 
• Ovarian cysts – this is uncommon 
• Vaginal bleeding and pain – this is uncommon

Do IUDs make you gain weight?

Weight gain is not listed as a side effect with the copper coil, as there is no evidence to support it. However, studies have shown that women tend to put on weight as they age regardless of their contraception.

Does an IUD stop periods?

The IUD/copper coil can make your periods heavier, longer and more painful. You may also notice spotting or bleeding between your periods. This won’t happen for all women, and if it does you may find that your periods improve after a few months.

The IUS/hormonal coil can make your periods a lot lighter, shorter and less painful – for some women, periods stop altogether. 

Risks of an IUD

In rare cases, having a coil inserted can lead to:

• pelvic infection
• damage to the womb
• increased risk of ectopic pregnancy 

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.

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.

What are the pros and cons of an IUD?

Before having the contraceptive coil fitted you may want to consider whether it is right for you as an effective method of contraception. You may want to chat about your choice with friends or family to see what experiences anyone you know has had with the copper coil.

Where can 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.

Alternative contraception

There are lots of different contraceptive options if the coil isn’t your first choice. 

• Combined pill - The combined pill uses synthetic forms of progestogen and oestrogen to prevent pregnancy. You usually take it for 21 day and then have a four or seven-day break, during which you’ll have a withdrawal bleed (which is like a period, but isn’t one).
• Progestogen-only pill - Sometimes called the mini pill, the progestogen-only pill, uses a synthetic form of progestogen to prevent pregnancy. You’ll have to take this kind of pill every day, with no break.
• Contraceptive patch or ring - Both the patch and ring are considered ‘combined contraceptives’ because they also use progestogen and oestrogen to prevent pregnancy. The patch is worn on the skin. The ring is inserted into the vagina.
• Contraceptive implant/injection - The implant and injection use artificial versions of progestogen to avoid pregnancy. The implant is a small device inserted into the arm - it can last up to three years. With the injection, you’ll need to have it administered by a clinician around every 13 weeks. 

Conclusion

The coil (IUD/IUS) is inserted into the uterus by a doctor or nurse. It’s a long-acting form of contraception that can stop you getting pregnant for up to 10 years. There are advantages and disadvantages to the coil, so only you can decide if it’s right for you.

References

https://www.nhs.uk/contraception/methods-of-contraception/iud-coil/
https://www.nhs.uk/contraception/methods-of-contraception/ius-hormonal-coil/
https://www.researchgate.net/publication/10647479_Weight_variation_in_a_cohort_of_women_using_copper_IUD_for_contraception