What to Know About the Contraceptive Coil

When should I use the contraceptive coil?

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The contraceptive coil is small, plastic, and T-shaped, and can be fitted into your womb by a doctor or nurse. It gives long-term protection against pregnancy.

What is a contraceptive coil?

The contraceptive coil is a type of device fitted in the vagina to help avoid pregnancies. There are two main types of coil available:

  • The copper coil – this coil is coated with copper and is referred to as an ‘intrauterine device’ (IUD)
  • The hormonal coil – this coil is coated with the sex hormone, progesterone and is referred to as the ‘intrauterine system’ (IUS)

What’s the difference between a copper and hormonal coil?

Both coils give long-term contraception and work in similar ways to prevent fertilisation.

The copper coil releases copper, which creates an environment in your womb where sperm can’t survive. It also changes your cervical mucus to prevent sperm from fertilising an egg.

The hormonal coil releases progesterone, which changes your cervical mucus to prevent sperm from fertilising your egg. It may also prevent your ovaries releasing mature eggs.

Copper coils can last for 10 years and hormonal coils can last for either 3 or 5 years. Both are highly effective for preventing pregnancy.

What are the advantages and disadvantages of contraceptive coils in general?


  • They work straight away once they’re fitted
  • You don’t have to think about contraception every time you have sex
  • Most women can use them
  • It’s possible to become pregnant as soon as a coil is removed
  • The copper coil can be used for emergency contraception if inserted within 5 days after unprotected sex


  • They don’t protect against sexually transmitted infections (STIs) so you need to consider using a condom as well
  • You need to attend regular check-ups with your doctor or nurse
  • You need to check at regular intervals that it’s in place. Your doctor or nurse can help you learn how to do this, or there is plenty of online content to help you. It’s done by feeling a thin thread that hangs down from the top of your vagina.
  • It may slip out of place or your womb may force it out. Both of these are uncommon, but they’re more likely to happen soon after a coil is fitted. Never try to put a coil back in place by yourself

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What are the advantages and disadvantages of a hormonal coil?


  • It can make your periods much lighter or less painful after 3 to 6 months
  • It may be used to treat endometriosis and heavy periods
  • Can be used during breastfeeding
  • May be a good option to consider if you can’t take oestrogen, which is found in the combined contraceptive pill


  • Side effects are more common, but usually disappear after the first 3 to 6 months
  • There are more medical considerations before fitting, such as if you’ve had breast cancer
  • It can interact with some medications

What are the advantages and disadvantages of a copper coil?


  • It lasts longer than the hormonal coil
  • It doesn’t cause most side effects as it doesn’t rely on hormones to work
  • An exception to this is the possibility of heavier periods
  • It doesn’t interact with other medications


  • You may experience more periods that are heavy or painful. This is more likely if you’re already prone to them

How do I choose which type of coil is for me?

Which coil you choose will be based on a combination of your medical history, a doctor’s advice, and your own preference if you have one.

Some factors to help you decide include:

  • How long you want the coil to be effective for – the copper coil can be effective for five more years than the hormonal coil
  • The copper coil doesn’t contain any hormones. This means it can be more suitable if you can’t use the hormonal coil either because of your medical history or if you’re at risk of hormonal side effects
  • The hormonal coil can be useful for treating other medical conditions such as endometriosis
  • Both are over 99% effective

How effective is the coil?

The coil is over 99% effective at preventing pregnancy. Once it’s fitted, it works straight away.

Coils have ‘perfect use’, meaning that once they’re fitted correctly, they’re always at maximum effectiveness. The only maintenance required is for you to check it’s in place at regular intervals and attend check-ups.

This is compared to a contraceptive like the Pill, where the effectiveness is much lower in actual use because people don’t always take it perfectly.

The only other contraceptive with ‘perfect use’ is the contraceptive implant.

Some other contraceptive methods are less effective with ‘typical use’, which happens when the method isn’t always used correctly. If any contraception is not used correctly, it’s less effective.

In comparison to the coil, the following contraceptive methods have a lower effectiveness with ‘typical use’:

  • Injection
  • Vaginal ring
  • Patch
  • Combined contraceptive pill
  • Progesterone-only pill
  • Male or female condoms
  • Diaphragms and caps
  • Natural family planning

What makes the coil more effective?

  • Making sure your coil is inserted by an experienced doctor or nurse to reduce the risk of any rare complications
  • Checking your thread at regular intervals to ensure your coil is in place
  • Attending regular check-ups with your doctor or nurse

What makes the coil less effective?

  • Vaginal inflammation or a pelvic infection
  • There’s a higher risk of your womb expelling the coil if you are under 20 years old, have never been pregnant, or you have already expelled a coil before
  • Fibroids (benign growths on the womb), which pose a risk of pushing the coil out
  • Having an existing STI (sexually transmitted infection)

Who can use the coil?

The coil can be used by sexually active women who want long-term contraception, even if they’re under 16.

If you’re under 16, your doctor or nurse won’t tell your parents or carer as long as they’re satisfied that you fully understand all the information given and the decisions your making.

You can’t get any type of coil fitted if you’re pregnant or think that you could be pregnant.

You can’t use the copper coil if you:

  • are prone to heavy and painful periods. It can make these symptoms worse
  • have a copper allergy

You can’t use the hormonal coil if you:

  • have had, or do have, breast cancer, cancer of the womb, cervical cancer, or liver cancer
  • have a pelvic infection or vaginal inflammation
  • have fibroids that pose a risk of pushing the coil out
  • have a STI
  • have current or repeat pelvic inflammatory disorder
  • have hypersensitivity to any of the ingredients in the hormonal coil

How do you get the coil?

Both types of contraceptive coil are available for free on the NHS (even if you’re under 16).

You can get the coil at:

  • GP surgeries
  • contraception clinics
  • sexual health or genitourinary (GUM) clinics

Whether you can get one fitted depends on whether the coil is right for you. Your GP or nurse will check this before they recommend the coil for you.

Contraception if you’re under 16

Health care professionals work to strict guidelines for people under 16 years of age.

Contraceptive services are always treated as confidential. If you’re under 16, they’ll encourage you to tell your parents or carer, but they won’t make you. The only time they might discuss it with someone else is if they believe you are at risk of harm. Even then, they would usually still discuss it with you first, as the risk would need to be serious.

Can you get side effects from the coil?

Side effects can happen with any medicine, but not everyone gets them.

Side effects of the copper coil

Most common:

  • heavier and more painful periods. This is even more likely if you often have heavy and painful periods normally

Other side effects are uncommon but include:

  • Nausea
  • Cramps
  • Backache
  • Vaginal discharge
  • Inflammation of the vagina
  • Pelvic infection
  • Ectopic pregnancy (egg implanting outside the womb) – very small risk but very serious

Side effects of the hormonal coil

The most common are:

  • Headaches
  • Feeling sick (nausea)
  • Mood swings
  • Worsening of pre-existing acne
  • Breast tenderness
  • Irregular bleeding

These side effects are most common during the first 3 to 6 months, and usually disappear after a few months.

How do I manage these side effects?

  • Feeling sick (nausea) – eat small portions of light meals each day and drink plenty of water. Avoid fatty, fried and strong-smelling foods
  • Backache, headache, or cramps – If you can take them, try a simple painkiller such as paracetamol to help relieve pain
  • Mood swings – keep to a regular sleep pattern, and make sure you get enough sleep. This can help you manage mood swings and keep your stress levels low
  • Acne – some acne treatments are available from pharmacies if your symptoms are bad or impact your life
  • Irregular bleeding – speak to a doctor if you have irregular bleeding that lasts for a long time, or an unusual vaginal discharge which is bothering you

See your doctor if you develop possible signs of an infection soon after your coil is fitted. Symptoms include:

  1. A smelly discharge
  2. High temperature
  3. Pain in your lower abdomen

In rare cases, fitting of the coil can damage your womb by making a small hole in it. The risk is very low if an experienced doctor or nurse is fitting it. See your doctor if you experience pain after fitting. This can often cause no symptoms.

Ectopic pregnancy

There’s a small risk of an ectopic pregnancy (pregnancy occuring outside the womb) if your coil fails and you become pregnant. An ectopic pregnancy is serious, so it’s important to seek help quickly – even if you have had a negative pregnancy test result.

Try and get immediate medical attention from your nearest Accident & Emergency department if you experience any of the following and think you may be pregnant:

  • A sudden sharp intense pain in your stomach
  • Feeling very dizzy or sick
  • Fainting
  • Looking very pale
  • Shoulder tip pain
  • Vaginal bleeding which is different from your regular period. It may be watery or dark brown in colour

Is the coil safe?

The coil is a safe method of contraception, but it does have a few rare complications.

A complication of the contraceptive coil mean another condition that is caused by the coil.

These are the rare complications that the coil can cause:

  • Pelvic infection – most likely in the first 20 days
  • Rejection – soon after the coil is fitted your womb may expel it or it may become displaced
  • Damage to the womb – very rarely, the coil may make a hole in your womb when it’s being fitted. The risk is extremely low if the doctor or nurse fitting it is experienced.
  • Ectopic pregnancy

Are there any myths about the contraceptive coil?

Some myths do exist about the contraceptive coil, but it remains one of the most effective methods of contraception.

  • Abortion. The coil doesn’t work by causing abortions. It prevents fertilisation by releasing copper or the hormone progesterone
  • Weight gain. There is currently no evidence that the either the copper or hormonal coil will affect your weight
  • Length of effectiveness. It remains effective even after a few years. The effectiveness doesn’t reduce with the number of years of use, until it is time to change the coil
  • Infertility. It doesn’t affect fertility and you can get pregnant as soon as your coil is removed. Long term use of a coil isn’t associated with infertility
  • Ectopic pregnancy or miscarriage after removal. The coil doesn’t cause an increased risk of ectopic pregnancy or miscarriage once removed
  • Moving in the body. It never travels to any other organ in your body but stays securely in your womb. Your womb may expel the coil soon after it’s fitted, but this is uncommon
  • Copper toxicity. The copper in the coil is not released into your bloodstream. Long term levels of copper are similar to those who don’t use the coil
  • Other health risks: there’s no evidence that links the use of the coil to cancer, birth defects, or STIs
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