Coils for contraception: What you need to know

• The coil is an effective form of contraception
• There are two main types of coil: the hormonal coil, known as the intrauterine system (IUS) and the intrauterine device (IUD) made of copper and plastic
• Find out about the key differences between types of coils, plus advice on having a coil fitted

The coil is a type of long-acting reversible contraception which is effective and reversible. Once it has been fitted you can forget about it for a number of years, so it’s ideal if you struggle to remember to take the oral contraceptive pill every day.

There are two main types of coil: the hormonal coil, which is known as the intrauterine system (IUS), and the intrauterine device (IUD) which is made of copper and plastic.

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What is a hormonal coil or IUS?

A hormonal coil, or IUS, is a small, flexible T-shaped device that steadily releases the hormone progestogen over a period of up to five years. It needs to be inserted or removed by a doctor or nurse, and when fitted correctly it’s more than 99% effective. It can also be used as a treatment for heavy or painful periods, and as part of your HRT.

There are three main types of hormonal coil:

1. Mirena: this contains a hormone called levonorgestrel, which is type of progestogen. It can be left in place for five years, or longer if you are over the age of 45 when it is inserted and it used for contraception only. The Mirena can also be used as the progesterone element of your HRT. There is another coil which is very similar called Levosert which contains the same progestogen, in the same 52mg dose as the Mirena with the same benefits of providing contraception and the progesterone component of HRT.  Both the Mirena and Levosert can also be used as a treatment for heavy periods. 
2. Kyleena: this is a slightly smaller, lower-dose version of the Mirena, which can also be left in place for five years. The smaller size means that it may be suited to those who have not previously been pregnant. Kyleena can be used for contraception only, not HRT.
3. Jaydess: another smaller, lower-dose coil, which can be left in place for three years. This is the lowest dose option and is not suitable for using as part of your HRT.

How does the hormonal coil work?

When the hormone progestogen is released into your womb, this thickens the mucus from the cervix, making it difficult for sperm to reach an egg. Progestogen also thins the lining of the uterus so that it’s less likely to accept a fertilised egg. For some people, it can also stop the release of an egg (ovulation). Once removed, your fertility will return to normal.

What is a copper coil or IUD?

The copper coil, or IUD, is a small, T-shaped plastic device which has areas coated in copper. It is inserted into the uterus by a doctor or nurse and can stay in place for up to ten years, depending on your age and the type of coil fitted. This type of coil doesn’t contain any hormones. When fitted correctly, it is more than 99% effective.

Different copper coils last five to 10 years for contraception. Sometimes copper coils can be relied upon for more than 10 years if fitted after the age of 40.

Copper coils lasting five years tend to be smaller and can sometimes be more appropriate for women who have not had children.

How does the copper coil work?

The copper prevents sperm from surviving in your cervix or womb, which means they are unable to reach an egg. In the rare event that sperm survives and reaches an egg, the presence of the IUD can stop a fertilised egg from implanting. Once removed, your fertility will return to normal.

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How do I know which type of coil is right for me?

The hormonal coil (IUS) is a good choice for those who can’t use contraception containing estrogen, perhaps due to migraines. It can also be beneficial if you have heavy or painful periods, as bleeding usually becomes lighter, or stops altogether, once it’s in place.

The copper coil (IUD) is suitable for most women and is popular with those who can’t – or don’t want to – use hormonal methods of contraception. It can also be fitted as an effective form of emergency contraception if you have had unprotected sex.

How is a coil fitted?

Having both types of coil fitted is a straightforward process which is carried out by a trained doctor or nurse at a GP surgery, sexual health or contraception clinic, or a private clinic. A speculum, similar to the type used for cervical screening, is used to open up the vagina, and the coil is inserted through the cervix and into the uterus. Once fitted, two fine threads attached to the coil remain at the top of the vagina. This makes it easy for you, or a health professional, to check that the coil is still in place. This also makes it easy for a doctor or nurse to remove it easily when required.

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Does it hurt to have a coil fitted?

Many people worry that it will be painful to have a coil fitted, and most people do find it uncomfortable. You can expect some period-like cramping during and after the fitting, but a local anaesthetic gel is used to reduce any pain or discomfort. The appointment takes about 20 minutes from start to finish, but the fitting should take no more than about five minutes. You can also take over-the-counter painkillers such as paracetamol or ibuprofen to help. Let the healthcare professional fitting the coil know if you’re finding it painful as they can stop at any time.

When can I have a coil fitted?

A coil can be inserted at any point in your cycle, as long as you’re not pregnant. You can usually have a coil fitted four weeks after giving birth, but in some cases, it can be fitted just 48 hours after giving birth. Any additional considerations will be discussed with you prior to having a coil fitted if you have recently given birth.  A coil can also be fitted straight after a miscarriage or termination.

How quickly does a coil start working?

When fitted within seven days of your last period, a coil is effective as a form of contraception right away. If it’s fitted at any other time, you’ll need to use another method of contraception, such as condoms, for seven more days.

If you’re having a Mirena coil fitted as part of your HRT, you can stop taking progesterone straightaway.

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Can I expect any side effects?

Some people experience hormonal side effects such as mood swings, breast tenderness and acne when using a hormonal coil (IUS). You can expect some bleeding or spotting when it’s first fitted, but your periods may then become lighter, irregular or stop completely.

When using a copper coil (IUD) your periods should come at the usual time but may get longer, heavier or more painful in the first 3-6 months. You may also get some spotting or bleeding in between periods, and may have a slightly increased risk of getting thrush that keeps coming back.

There’s a very small risk of getting a pelvic infection in the first few weeks after a coil has been inserted, so it’s important to speak to your doctor if you have pain or tenderness in your lower abdomen, a high temperature, or an abnormal or smelly discharge.

There’s also a small chance that a coil can be displaced or rejected soon after it has been fitted, but the doctor or nurse who fits it will explain how to check for the threads so that you know it’s still in the correct position.

A rare, but serious, complication of having a coil fitted is perforation of the womb. This is when a small hole is made in the womb during the fitting procedure.  It can present with severe pain, heavy bleeding and an inability to feel the coil threads.

Occasionally people report that their partner can feel the threads during sex. If this happens, make an appointment with your doctor or nurse for the threads to be trimmed.

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How do I get a coil removed or changed?

Removing or changing a coil is a straightforward process which can be carried out at any time by a trained doctor or nurse. A speculum is used to open up the vagina and locate the two fine threads attached the coil. When these are gently pulled, the coil comes out. Again, a local anaesthetic gel can be used to minimise any discomfort.

It’s possible to get pregnant as soon as a coil has been removed. If you’re not having another coil fitted, and rely on it for contraception, you should use additional contraception, such as condoms, for seven days before your appointment.