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.

Photo of hormonal IUD
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
Both Mirena and Kyleena are very effective methods of contraception. Kyleena lasts for up to 5 years and Mirena lasts up to 8 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.
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 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.
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.
The hormonal IUD might not work if it:
Other possible side effects for a small number of users can include:
These side effects nearly always settle with time. The hormonal IUD has not been shown to cause weight gain.
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.
Once the hormonal IUD is in for more than 5 years for Kyleena and 8 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.
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.
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.
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.
Copyright © 2025 Sexual Health Victoria. All rights reserved.