The hormonal intrauterine device (IUD) is a type of long-term birth control (contraception). It’s more than 99% effective – meaning 99 out of 100 women don’t get pregnant while using it. It can also help with conditions such as heavy periods.
“A hormonal IUD is very convenient: once it’s been fitted, you don’t need to think about it, so you’ll never forget contraception – or need to rely on someone else to bring it,” says Dr Adiele Hoffman, family doctor and Healthily expert. “And it can be a great choice if you have heavy periods. At first, you may get some spotting and irregular bleeding, but this usually settles if you stick with it for a few months.”
So read on to learn all you need to know about this type of hormonal contraception.
What is the hormonal IUD?
A hormonal IUD is a tiny T-shaped device made of plastic, which can be fitted into your womb (uterus) by a doctor or nurse. You won’t feel it once it’s in place.
It's also sometimes known as a:
- intrauterine system (IUS) – this term is mainly used in the UK
- hormone-releasing IUD
- hormonal coil
- levonorgestrel-releasing IUD (LNG-IUD)
- levonorgestrel-releasing IUS
“It can be quite confusing, but they’re all talking about the same thing,” says Dr Adiele.
How is the hormonal IUD different from the non-hormonal (copper) IUD?
Unlike the non-hormonal IUD, a hormonal IUD:
- releases hormones
- doesn’t contain copper – it’s made of a plastic called polyethylene
- can’t be left in place for as long
How does the hormonal IUD work?
It releases small amounts of hormones called progestins into your womb to stop you getting pregnant. These are a medical version of the progesterone your body makes naturally.
Progestins can prevent pregnancy in 3 ways:
- they can make it harder for sperm to reach an egg by thickening the mucus that comes from the neck of your womb (cervix)
- they can stop a fertilized egg from embedding (implanting) in your womb lining (endometrium), by making it thinner
- higher-dose devices, such as the Mirena, can sometimes stop your ovaries from releasing an egg (). This is less likely to happen with lower-dose devices
There’s no evidence that hormonal IUDs act like an
by disrupting an implanted pregnancy – instead, they stop pregnancy happening in the first place.
What are the different types?
In the US, there are 4 brands of hormonal IUD available: Mirena, Skyla, Liletta and Kyleena.
They all work by releasing small amounts of progestins – they just use different doses. They’re also different sizes, and for birth control they’re licensed to stay in place for different lengths of time:
- Mirena works for up to 8 years and provides a 52mg dose
- Liletta works for up to 6 years, also with a dose of 52mg
- Kyleena works up to 5 years and the dose is 19.5mg
- Skyla works for up to 3 years with a dose of 13.5mg
How does it get fitted?
Like a non-hormonal IUD, it has to be fitted for you by a medical professional. Read about how IUDs are fitted.
Could a hormonal IUD be right for you?
A hormonal IUD may be suitable for you if:
- you’re looking for long-term contraception – it can stay in place for up to 8 years
- you want birth control that’s quickly reversible – you can try for a baby as soon as you have it taken out
- you don’t want to have to remember to take a pill every day
- you find condoms interfere with the spontaneity of sex
- you’re a new mum – it’s safe to use while breastfeeding
- you’re taking medications that other types of contraception can interact with
- you can’t use contraception that contains estrogens – such as the or the contraceptive patch or ring
- you’re menopausal – the Mirena can be used as part of to protect the lining of your womb for up to 5 years. Read more about the
- you have a health condition that a hormonal IUD can help treat
Conditions the hormonal IUD can help with
In the US, 52mg hormonal IUDs (such as Mirena) are licensed to treat heavy bleeding. All other uses are ‘off-label’ – this means it’s outside the use it’s licensed for, but your doctor can prescribe it on the basis that it’s supported by strong medical evidence.
Why a hormonal IUD might not be right for you
The hormonal IUD isn’t suitable for everyone. It may not be the best choice if:
- you want or need to avoid using hormones – such as if you have history of breast cancer
- you want contraception that protects against as well as pregnancy – are the only type of contraception that does this
- you’re not looking for long-term birth control – if you’re paying for for an IUD, the upfront cost can be high, and it’s a more invasive type of birth control
- you have an infection, such as an STI or
- you have unexplained vaginal bleeding, such as between periods or
- you have problems with the size and shape of your womb – your doctor or nurse will examine you before fitting an IUD
- you have liver disease
- you’re pregnant – the health professional fitting your IUD will make sure you aren’t pregnant. It’s best to have it inserted during the first 7 days of your cycle
Hormonal IUD side effects and risks
Side effects of the hormonal IUD can include:
- changes in your period pattern – including spotting, irregular bleeding and bleeding for longer. This is common in the first 3 months and will usually settle down, but about 1 in 5 people still have it after a year. Some people have no periods at all
- headaches, acne, breast tenderness and mood changes – these hormonal side effects are thought to affect between 1 in 10 and 1 in 100 people. They’re most common in the first few months, and usually go away over time
- – these small fluid-filled sacs can develop in between 1 in 10 and 1 in 100 people. Most don’t cause any symptoms and go away after a few months
Risks of using the hormonal IUD include:
- infection – it’s possible to get a pelvic infection in the first few weeks after having an IUD fitted. If you’re at risk of a sexual infection, you’ll be tested before insertion and treated to stop a pelvic infection developing. Warning signs include pain or tenderness in your lower tummy, a high temperature (fever) and smelly vaginal discharge
- expulsion – in about 1 in 20 people, an IUD can fall out. It’s most common in the first 3 months after insertion. This is why it’s important to check your IUD hasn’t moved
- – if your device fails and you get pregnant, there’s an increased risk of an ectopic pregnancy, although overall the risk is lower than it would be without using an IUD at all
- perforation – there’s a small risk of the device making a small hole in your womb when it’s fitted. This happens in up to 2 in 1,000 insertions, though the risk is 6 times higher if you’re breastfeeding
How to check your IUD hasn’t moved
After you’ve had your IUD fitted, your doctor or nurse will recommend you do a monthly check on the plastic threads/strings that hang down from the IUD into your vagina (which are there so the device can be removed).
If you can’t feel the threads, this may mean your IUD has moved, so you should contact your doctor. Read more about how to know if your IUD has moved.
Read about if you can feel an IUD during sex.
When to see a doctor
Your doctor can help you get the best from your hormonal IUD by:
- fitting it for you – the device needs to be fitted and removed by a health professional in a hospital or clinic setting. Read about IUD insertion
- making sure it’s working well throughout the years you use it
You should also see your doctor if:
- you can’t feel your threads, or you think your IUD has fallen out. You should make sure you use additional birth control if this happens, as you may not be protected. You might also need a scan to check where your IUD is. It’s usually still in your womb, though in rare cases – such as if you have a perforation – it can move into your abdomen. Occasionally, you’ll need a procedure or operation to remove it
- you’re getting side effects that are bothering you or aren’t settling down
- you want to have it removed – read about IUD removal
When to see a doctor urgently
You should see a doctor right away if you’ve had an IUD fitted and get signs of an infection, such as:
- a high temperature (fever)
- pain or tenderness in your lower tummy
- smelly vaginal discharge
- pain during sex
When to get emergency medical help
Although most people have hormonal IUDs inserted without any complications, there are some warning signs to watch out for. They may mean you have pelvic inflammatory disease, a perforation, or an ectopic pregnancy.
You should go the emergency department if you have symptoms such as:
- severe tummy pain – this can be sharp and is usually sudden
- heavy bleeding
- feeling dizzy, faint or very unwell
Your health questions answered
Does the hormonal IUD make you gain weight?
“It hasn’t been shown that hormonal IUDs can make you put on weight,” says Dr Adiele. “There has been lots of research into weight gain and hormonal IUDs, but it’s a difficult area because of other influencing factors. Women of reproductive age tend to have weight changes anyway, regardless of whether they’re using hormonal contraception. But studies have compared hormonal and non-hormonal IUDs, and found no difference in weight gain. Try to keep to daily calorie limits and stay physically active to avoid gaining weight.”