Finding a contraceptive method that fits seamlessly into your life can feel like a game-changer, giving you one less thing to think about. The coil is one of the most popular and effective long-acting reversible contraception (LARC) methods available in the UK. You’ve likely heard of two main types: the copper coil (IUD) and the hormonal coil (IUS).
While they look almost identical and are both over 99% effective, they work in fundamentally different ways and can have a vastly different impact on your body and your periods.
Choosing between them can feel daunting, but it doesn’t have to be. Let’s walk you through the key differences, from how they work to what you can expect during the fitting, so you can feel empowered and confident in the choice that’s right for your body and your lifestyle.
The two types of coil
At their core, both coils are small, T-shaped devices that are expertly placed inside your womb (uterus) by a healthcare professional to prevent pregnancy. But their approach to preventing pregnancy is quite different.
The copper coil (IUD)
The Intrauterine Device, or IUD, is your non-hormonal option. It’s a small plastic frame carefully wrapped with a tiny amount of natural, safe copper.
- How it works: The IUD works by releasing copper ions into the womb. This creates an environment that is toxic to sperm, preventing them from surviving long enough to reach and fertilise an egg. It also causes a mild inflammatory response in the uterine lining, which stops a fertilised egg from implanting. It’s a simple and effective mechanism with no hormones involved.
- Duration: Depending on the specific type, a copper IUD can provide protection for 5 or even 10 years.
- Features: Because it’s hormone-free, the IUD won’t affect your natural cycle. It’s effective from the moment it’s fitted and can also be used as the single most effective method of emergency contraception if inserted within five days of unprotected sex.
Image by Freepik
The hormonal coil (IUS)
The Intrauterine System, or IUS, is the hormonal option. It looks very similar to the IUD but contains a small reservoir of a progestogen hormone (levonorgestrel), which it releases in tiny, steady amounts directly into the womb.
- How it works: The IUS works in three clever ways. Firstly, it thickens the mucus at the neck of your womb (cervix), creating a barrier that sperm can’t get through. Secondly, it thins the lining of the womb, making it unsuitable for a fertilised egg to implant. For some women, it may also prevent ovulation (the release of an egg). Because the hormone acts locally, the amount that enters your bloodstream is significantly lower than with options like the contraceptive pill.
- Duration: There are several brands of IUS available in the UK, which last for between 3 and 8 years. At Summerhill Health, we use Mirena, Kyleena, and Jaydess.
- Features: If an IUS is fitted within the first 7 days of your period starting, it’s effective immediately. If fitted at any other time, you’ll need to use condoms for 7 days to be safe.
Image licensed under the Unsplash+ License
Let’s talk about periods and the coil
For many women, the biggest difference between the IUD and the IUS—and often the deciding factor—is how each one affects their monthly cycle.
Life with a copper IUD
Because the IUD is hormone-free, your body will continue its natural menstrual cycle. However, it’s important to be aware that a common side effect, particularly in the first 3-6 months, is that your periods may become heavier, longer, or more painful than before. For some women, this settles over time, but if you already struggle with heavy or painful periods, the IUD might not be the most comfortable choice for you.
Life with a hormonal IUS
The hormonal IUS has a very different effect on periods; one that many women see as a major advantage. The progestogen hormone thins the uterine lining, which typically leads to periods becoming significantly lighter, shorter, and less painful. After a year of use, around 1 in 5 women find their periods stop altogether—which is perfectly safe and often seen as a major benefit.
With both types of coil, it’s common to experience some irregular bleeding or spotting for the first few months as your body adjusts. We know it can be frustrating, but patience during this initial phase really is key.
Image licensed under the Unsplash+ License
A side-by-side comparison of the IUD vs IUS
To make things even clearer, here’s a quick-glance table summarising the key points:
| Feature | Copper Coil (IUD) | Hormonal Coil (IUS) |
|---|---|---|
| Type | Non-Hormonal | Hormonal (Progestogen) |
| How it Works | Releases copper ions, toxic to sperm. | Thins uterine lining & thickens cervical mucus. |
| Effectiveness | >99% | >99% |
| Duration | 5 to 10 years | 3 to 8 years (brand dependent) |
| Effect on Periods | Can become heavier, longer, and more painful. | Usually become lighter, shorter, less painful, or may stop. |
| Hormonal Side Effects | None. | Possible initially (e.g., acne, headaches, breast tenderness), but these often settle. |
| Non-Contraceptive Use | Highly effective emergency contraception. | Treats heavy periods, endometriosis symptoms, and can be part of HRT. |
| Best For | Women who prefer a hormone-free option and have manageable periods. | Women with heavy/painful periods, or those seeking lighter/no periods. |
Other benefits of the hormonal coil (IUS)
While the copper IUD’s main job is contraception, the hormonal IUS can be a true multitasker for your health. The IUS is recognised as a first-line treatment for heavy menstrual bleeding (menorrhagia) and can be so effective that it helps many women avoid more invasive surgery. It can also reduce the debilitating pain associated with conditions like endometriosis and adenomyosis.
For women experiencing perimenopause and menopause, the IUS plays an important role in Hormone Replacement Therapy (HRT). It provides the necessary progestogen to protect the lining of the womb when taking oestrogen, all while delivering excellent contraception.
What to really expect when getting the coil fitted
The thought of having a coil fitted can cause some anxiety, but understanding the process can make it feel much more manageable. It’s a quick and straightforward procedure performed by a specially trained doctor or nurse.
Image licensed under the Unsplash+ License
Before your appointment
First, you’ll have a comprehensive consultation. This isn’t just a tick-box exercise; it’s your opportunity to discuss your medical history, lifestyle, and any worries you have. We’ll ensure it’s the right choice for you and answer all your questions. Depending on your circumstances, we may also perform an STI screening or a pregnancy test for your safety.
The procedure itself
The fitting appointment usually takes about 15-20 minutes from start to finish. Here’s a rundown of what happens:
- It’s very similar to having a smear test and is always performed under sterile conditions.
- Your clinician will gently insert a speculum to help them see your cervix.
- They will then clean the area, and a small instrument is used to measure the depth of your womb to ensure a perfect fit.
- Finally, the coil is gently guided into place using a thin applicator tube.
- A great clinician will explain every step as it’s happening, so you are always in control and know what to expect.
Let’s talk about comfort
This is the question on everyone’s mind: does it hurt? The experience is different for everyone. Most women describe a short, sharp, period-like cramp as the coil is placed.
We always recommend taking painkillers (like ibuprofen) an hour before your appointment to help minimise this. For those who are particularly anxious or sensitive, local anaesthetic options are available to make the process as comfortable as possible. Your comfort is our priority.
After your fitting & recovery
Once your coil is in, you’re all set. You’ll be given clear post-procedure care instructions and guidance on what to expect during recovery.
- Most women can return to their normal activities straight away.
- It’s completely normal to experience some mild, period-like cramping for 24-48 hours afterwards.
- You may also have some light spotting, which can last for a few days or, in some cases, a few weeks as your body adjusts.
- We advise taking it easy for the rest of the day—it’s the perfect excuse to have a nap or curl up on the sofa!
We will explain how to check for the coil’s threads and discuss any follow-up arrangements. Our goal is to ensure you have complete peace of mind.
Image licensed under the Unsplash+ License
Which coil is for you?
Ultimately, the choice between an IUD and an IUS is a deeply personal one. It comes down to what you prioritise for your health and lifestyle.
- If you value a hormone-free method and are comfortable with your current periods, the copper IUD could be your perfect match.
- Or, if you would welcome lighter, less painful periods (or even none at all!) and could benefit from the other health perks, the hormonal IUS might be the ideal choice.
The good news is that you don’t have to compromise on reliability. Both coils are among the most effective contraceptives available, allowing you to get on with your busy life with complete peace of mind.
The most important step is to have a conversation with an expert who can listen to your needs and guide you toward the best solution for you.
Ready to explore your options? We invite you to learn more about our women’s health services. When you’re ready for a personalised chat, you can book a comprehensive contraception consultation with Dr Natalie Summerhill at Summerhill Health.