Hormonal coil

What is a hormonal coil?

A hormonal coil, also called an IUS (intrauterine system), is a small, T-shaped device made of plastic, fitted into your womb by a trained clinician. It prevents pregnancy by slowly releasing the hormone progestogen.

What is a hormonal coil used for?

The hormonal coil is mainly used for contraception, but it's also an effective option for heavy or painful periods and can supply the progestogen component of HRT for people going through the menopause.

What are the benefits of a hormonal coil?

The hormonal coil ranks among the most reliable contraceptive options, working for several years once fitted, so there's nothing to remember day to day. It doesn't interrupt sex, and many people find their periods become lighter, shorter, or stop altogether.

Fertility comes back without delay once it's taken out.

Are there different types of hormonal coil?

Several brands are on offer in the UK, Mirena among the best known, alongside Kyleena, Levosert and Jaydess. Each differs slightly in size and how much hormone it delivers, and how long they're licensed to stay in varies too, generally landing somewhere between 3 and 8 years, sometimes influenced by how old you are when it goes in.

What happens before a hormonal coil is fitted?

You can usually have a hormonal coil fitted at a GP surgery or sexual health clinic, at any point in your cycle as long as there is no chance you're pregnant.

• having something to eat beforehand can help if you're prone to feeling faint
• wearing clothing that's easy to remove can make things more comfortable
• you can bring someone with you, or ask for a chaperone, and you're free to pause or stop the appointment at any point
• your practitioner will explain the process and any risks, and answer your questions beforehand

You will usually be asked about the chances of having a sexually transmitted infection as well, since fitting a coil where one is already present can, in rare cases, push it further into the womb.

What happens during a hormonal coil fitting?

1. Your clinician examines you internally to check the size and position of your womb, using two fingers inside the vagina and a hand on your lower abdomen.
2. A speculum, similar to the one used for cervical screening, is used to hold the vagina open.
3. The coil, folded inside a narrow tube, is passed through the cervix into the womb.
4. The tube is withdrawn, allowing the coil to open into its T shape, leaving two thin threads passing through the cervix into the vagina.
5. The threads are trimmed to a suitable length. These let you or a clinician confirm it's sitting correctly and allow it to be removed later.

Fitting usually takes around 5 to 10 minutes, though the appointment as a whole may take about 30 minutes. Some people find it uncomfortable or painful, while others don't.

What does recovery look like?

Cramping, period-like pain and some light bleeding are common for a few days afterwards. Paracetamol, a hot water bottle or a warm bath can help ease this.

If it's fitted within 7 days of the start of your period, you're protected from pregnancy straight away. Fitted at any other time, you'll need to use additional contraception, such as condoms, for 7 days. Your practitioner will also let you know when it's safe to have sex again, sometimes after a few days, to help reduce infection risk.

It's worth checking the threads occasionally to make sure the coil is still in place. A small proportion, roughly one coil in twenty, works its way out unassisted, most commonly during the initial few months after it goes in.

What are the risks and side effects?

Possible risks and side effects of the hormonal coil include:

• infection, most likely within the first few weeks after fitting
• irregular or light bleeding, particularly in the first 6 months, which usually settles over time
• the coil coming out on its own, or shifting out of position
• a small chance, around 2 in 1,000, of the coil passing through the wall of the womb, most often at the time it’s fitted
• a higher chance of an ectopic pregnancy if you do become pregnant while using it, though this remains rare overall
• temporary side effects in the first few months, such as breast tenderness, headaches, acne or premenstrual-type symptoms

There's also a small increase in breast cancer risk associated with hormonal coil use, estimated at around 14 extra cases per 10,000 users between the ages of 15 and 49, compared with those not using hormonal contraception.

A hormonal coil doesn't protect against sexually transmitted infections, so you may still need to use condoms.