Hormonal Intrauterine Devices (IUDs) – (Mirena and Kyleena)

  • 99.7 to 99.9 % Effective
  • No STI Protection
  • 5 - 6 years

What are the hormonal intrauterine devices (IUDs)?

The hormonal IUDs are small ‘T- shaped’ plastic devices that are inserted into the uterus (womb). The hormonal IUDs contain progestogen. This is a synthetic version of the hormone progesterone made naturally by the ovaries. The hormonal IUDs have a coating (membrane) that controls the slow release of progestogen into the uterus. There are two different hormonal IUDs available in Australia. They are sold as Mirena and Kyleena.

Fpv Hormonal Iud
Photo of hormonal IUD

How effective are hormonal IUDs?

The hormonal IUDs are more than 99% effective at preventing pregnancy and can last for up to 6 years.

How does hormonal IUD work?

IUDs affect the way sperm move and survive in the uterus (womb), stopping sperm from meeting and fertilising an egg. IUDs can also change the lining of the uterus, making it difficult for a fertilised egg to stick to the lining to start a pregnancy.

Illustration of mucus in cervix

The hormonal IUDs also work by thickening the fluid around the cervix (opening to the uterus/womb). This helps to prevent sperm from entering.

Illustration of egg not sticking to uterus lining

Sometimes the hormonal IUDs can also stop the ovaries from releasing an egg.

Illustration of eggs not being released by ovaries

What are differences between Mirena and Kyleena hormonal IUDs?

Both Mirena and Kyleena are very effective methods of contraception. Kyleena lasts for up to 5 years and Mirena lasts up to 6 years. Mirena is 99.9% effective and Kyleena is 99.7% effective.

Mirena may be used until 55 years of age if inserted when you are 45 years of age or older, whereas Kyleena needs to be replaced every 5 years for all ages.

Kyleena is slightly smaller than Mirena and has a lower dose of the hormone, progestogen. Both hormonal IUDs will reduce vaginal bleeding (periods), however there are typically less bleeding or spotting days per month with Mirena than with Kyleena.

The choice between these two IUDs is a personal choice. You can speak with your doctor or nurse for more information.

Local anaesthetic: a medicine used to numb a part of your body for a short while. You remain conscious.

Sedation: a medicine used to cause a relaxed, sleep-like state so you are unaware of the procedure.

How do I use the hormonal IUD?

The hormonal IUD is inserted inside the uterus (womb) by a trained doctor or nurse. You can choose to have a local anaesthetic or sedation while it is inserted. The IUD insertion takes around 15 minutes but you will be in the clinic for an hour or more. See below for a video about IUDs and how to help prepare for and manage pain from an IUD insertion.

The IUD has a fine nylon string attached to it which comes out through the cervix (opening to the uterus/womb). The string cannot be seen and it does not hang out of the vagina. If you feel high up inside your vagina, you can check that the string is there and know the IUD is still in place. It is good to do this every month. If the string feels like it is shorter or longer than normal or you cannot feel the string at all, the IUD may have shifted and you should see a doctor or nurse.

Illustration of Hormonal IUD

When does it start to be effective?

When the hormonal IUD is inserted (put in) to the uterus (womb), it can take up to 7 days to start working to prevent pregnancy. This depends on the timing of your menstrual cycle and if you are already using contraception. Speak with your doctor, nurse or pharmacist for more information.

Where can I get the hormonal IUD?

Your doctor or nurse will provide a script which you can take to the pharmacy, who will sell you the hormonal IUD. You will need to return to the clinic to have the IUD inserted. If you do not have a Medicare card it will be more expensive. It will be cheaper if you have a healthcare card.

What stops the hormonal IUD from working?

The hormonal IUD might not work if it:

  • falls out (remember to check the strings regularly)
  • goes into the wrong position
  • is left in for longer than 5 years for Kyleena or 6 years for Mirena.

What is good about the hormonal IUD?

  • It is an extremely effective method of contraception.
  • Once inserted (put in) you will only need to check the string each month.
  • It can last up to 5-6 years or longer (Mirena only) if you have it inserted from 45 years of age.
  • You can use it while breast feeding.
  • No medications stop it from working.
  • Most users have no vaginal bleeding (period) at all or very light bleeding.
  • Periods may be less painful.
  • It can be taken out at any time by a doctor or nurse.
  • Once removed your fertility quickly returns to what is normal for you.
  • It is another contraceptive option if you have difficulty taking the hormone oestrogen. The Pill (combined pill or oral contraceptive pill) and vaginal ring (NuvaRing) contain oestrogen and progestogen. The hormonal IUD only contains progestogen.

Are there any side effects from using the hormonal IUD?

  • When the hormonal IUD is first inserted some users have period type cramping that usually settles after a few days.
  • Your vaginal bleeding pattern (period) will change. Spotting or frequent bleeding is common in the first 3 – 6 months. By 6 months most users will have a light regular period or no bleeding at all (this is not harmful to the body).
  • Sometimes the IUD can fall out. This is more common in the first 3 months of it being inserted.

Other possible side effects for a small number of users can include:

  • headaches
  • changes to your skin
  • sore/ tender breasts
  • mood changes.

These side effects nearly always settle with time. The hormonal IUD has not been shown to cause weight gain.

Can the hormonal IUD cause any serious health problems?

  • In about 1 in 500 users, the doctor or nurse makes a small hole in the wall of the uterus (womb) while inserting the IUD. The IUD can move through the hole and sit in the wrong place. You would then need keyhole surgery to have it removed.
  • Around 1 in 300 users get an infection when the IUD is first inserted. This is usually successfully treated with antibiotics.
  • It is very unlikely you will get pregnant when using the hormonal IUD. If you do get pregnant with a hormonal IUD, there is a higher chance of ectopic pregnancy. This means that the pregnancy may settle in the fallopian tubes (pathway of the egg to uterus).

Reasons why the hormonal IUD might not be a good option for you:

  • Have breast cancer or have been treated for breast cancer.
  • A uterus (womb) that is not the usual shape.
  • Severe liver disease.

What if I cannot feel the IUD strings?

If you cannot feel the IUD strings, you can abstain from sex or use condoms until a doctor or nurse confirms the IUD is in the right place. If you have had unprotected sex in the 5 days before you notice the string missing, you might need emergency contraception.

What if I am late having my hormonal IUD changed over or it has expired?

Once the hormonal IUD is in for more than 5 years for Kyleena and 6 years for Mirena, you can abstain from sex or use condoms until you can have it replaced. If you have unprotected sex and your IUD has been in for more than the recommended time you might need emergency contraception.

What happens if I get pregnant while I am using the hormonal IUD?

It is important that you see a doctor or nurse as soon as possible and have the IUD removed. The doctor or nurse will also need to rule out a pregnancy in your fallopian tubes (ectopic pregnancy). If the IUD is removed, you can continue the pregnancy or have an abortion. If the IUD cannot be removed and you continue the pregnancy, there is a higher risk of losing the pregnancy.

Find out more about having your IUD removed

Can I use the hormonal IUD after I have had a baby?

The hormonal IUD can be inserted straight after you give birth. If not inserted straight after you give birth, then you need to wait until at least four weeks later. The hormonal IUD is safe to use if you are breastfeeding.

What if I am using the hormonal IUD and I want to become pregnant?

The hormonal IUD can be removed at any time by a trained doctor or a nurse. Your fertility will quickly return to what is normal for you.

Find out more about having your IUD removed

What else should I know about the hormonal IUD?

  • The hormonal IUD does not protect you from sexually transmissible infections (STIs).
  • It is good to record the date or enter that date into your phone for when your IUD is due to be removed. You will need to have it taken out before it expires. You can have a new IUD inserted at the same time the existing one is being removed.
  • Your partner might be able to feel your IUD string during sex, but it rarely causes them discomfort.
  • The hormonal IUD is one of many types of contraception. See other contraceptive options

You might be interested in watching:

Current guidelines recommend that if you have a 52mg levonorgestrel IUD (Mirena) for contraception it can be used up to 6 years after being inserted .

Pain and IUD insertion – what to expect

Sexual Health Victoria's Medical Director Dr Kathy McNamee offers information to help prepare for and manage pain from an IUD insertion.

Where to get more information and support

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Last updated: 21 August 2023