The Coil: Everything you need to know

This is a detailed guide about the coil, covering key information about its effectiveness, types, and the process of getting one. When it comes to contraception, there are plenty of options, but one of the most effective and long-lasting choices is the intrauterine device (IUD), often called ‘the coil’. This guide covers everything you need to know about the coil, including how it works, its effectiveness, the differences between copper and hormonal coils, and what to expect during the insertion process. 

How does the coil work? 

An IUD is a small, T-shaped device placed in the womb to prevent pregnancy. It’s popular because it’s reliable and lasts for years. There are two main types: 

• Copper coil

  This type is non-hormonal and releases copper, which is toxic to sperm. It stops sperm from fertilising an egg and can also prevent a fertilised egg from attaching to the womb.

• Hormonal coil

  This type of coil releases progestogen, which acts locally to prevent pregnancy. It thickens the cervical mucus, blocking sperm from reaching the egg, and inhibits the growth of the endometrium (uterine lining), making it less likely for a fertilised egg to implant. 

Effectiveness of the coil 

The coil is one of the most effective contraceptives available. It’s over 99% effective, meaning fewer than 1 in 100 women using an IUD will get pregnant each year. 

• Copper coil: Over 99% effective. It can also be used as emergency contraception if fitted within five days of unprotected sex.
• Hormonal coil: Also over 99% effective, with some added benefits like reducing period pain and bleeding.

Both types are long-acting, reversible contraception methods, making them reliable choices for those looking for a hassle-free option.

Copper vs. hormonal coils 

Choosing between a copper and hormonal coil depends on your needs and health. 

Copper coil 

• No hormones: Great for those who want to avoid hormones. 
• Periods: Can cause heavier or more painful periods at first, but this might improve.
• Duration: Lasts up to 10 years.

Hormonal coil 

• Contains hormones: Can reduce period pain and bleeding. 
• Duration: Usually lasts 3 to 5 years.
• Extra benefits: Can help with heavy periods or conditions like endometriosis.

What to expect during IUD insertion 

Inserting an IUD is quick, usually taking around 5 to 10 minutes. Here’s what happens: 

• Preparation: You might get a local anaesthetic to numb the area. Some people take pain relief before the appointment.
• Insertion: The IUD is placed into the womb through the cervix with a thin, flexible tube. You might feel some cramping or discomfort.
• Afterwards: You may have cramping or light bleeding for a few days. Most people can get back to normal activities straight away.

A trained healthcare professional must insert the coil. In Ireland, it can be accessed through a face-to-face GP appointment and may be covered by the HSE's free contraceptive care scheme.

How long does an IUD last? 

How long an IUD lasts depends on the type: 

• Copper coil: Lasts between 5 and 10 years.
• Hormonal coil: Lasts between 3 and 5 years.

Both types can be removed at any time if you decide you no longer want it. Fertility returns to normal immediately after the removal of a copper coil and very quickly after the removal of a hormonal coil.

Possible side effects 

Most people get on well with the coil, but there can be side effects, especially at first. These might include: 

• Copper coil: Heavier or more painful periods, spotting between periods.
• Hormonal coil: Irregular bleeding, mood changes, or breast tenderness.

These side effects often settle down after a few months. If they don’t, talk to a healthcare provider. 

When to seek medical advice 

Get medical advice if you experience any of the following: 

• Severe pain or cramping that doesn’t improve. 
• Unusual or smelly vaginal discharge. 
• Heavy bleeding or periods that last much longer than usual. 
• Signs of infection, such as fever or chills. 

It’s always best to talk to a doctor if you’re worried about anything. You should also check the threads of the coil each month to make sure it’s in place. If you can’t feel the threads, use alternative contraception and see your doctor. 

HealthHero GP consultation and how we can help 

If you’re thinking about the coil or have any questions about contraception, a GP can offer personalised advice based on your health and lifestyle. At HealthHero, we offer online GP services that make it easy to get expert advice and prescriptions. Book a consultation today or find out more about your contraception options.