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The Facts About Mirena & Kyleena Hormonal IUDs

Updated: Apr 12, 2023

What is a hormonal IUD?

A Hormonal Intrauterine Device (IUD or IUS) is a small, flexible plastic T shaped intrauterine device that contains a small dose of a progestogen hormone called Levonorgestrel on the stem.

It is placed inside the uterus (womb) and works from the inside to prevent pregnancy for up to 5 years.

There are now two types of hormonal IUD available in Australia. The 52mg Levonorgestrel IUD (Mirena®) and the 19.5mg Levonorgestrel IUD (Kyleena®).

What is the difference between a Mirena® IUD and a Kyleena® IUD?

Both devices are licensed for contraceptive use up to 5 Year duration.

Mirena® IUD contains 52mg of Levonorgestrel and has three main indications for use:

  1. contraception

  2. menstrual control and

  3. the progestogen component of Menopausal Hormonal Therapy (Hormone Replacement Therapy).

It is particularly suited to women who have heavy periods or menstrual problems and those who may be approaching perimenopause. Mirena® can be used off-license for 7 years of contraception if inserted after the age of 45 years.

Kyleena® IUD is licensed for contraception only and has a smaller frame and insertion cannula compared to Mirena®. This makes it particularly suited to younger women, women with a small uterus and those who have never had a child.

Its lower hormonal dose means that it may not suppress periods as successfully as Mirena® IUD, but women may also experience less hormonal side effects including less risk of benign ovarian cysts with the lower dose system.

How does the hormonal IUD work?

Levonorgestrel IUD prevents pregnancy by thickening the cervical mucous to prevent sperm from being able to enter the uterus and by suppressing or thinning down the endometrium (uterus lining) to prevent a pregnancy from implanting.

Occasionally it will also stop ovulation.

How effective is a hormonal IUD at preventing pregnancy?

Mirena® IUD is 99.8% effective at preventing pregnancy. That means that there is a 0.2% chance that a woman with a Mirena® IUD will fall pregnant.

Kyleena® IUD is almost as effective at 99.7% at preventing pregnancy.

Advantages of Hormonal IUD:

  • It is a long-acting-reversible or “fit & forget” form of contraception, ideal for busy women.

  • Highly effective.

  • Cost effective as can be used for up to 5 Years.

  • Lightens periods and often women have no periods with the device (this is safe).

  • Reduced period pain.

  • Rapid return to fertility once removed.

Disadvantages of hormonal IUD

  • It does not protect against STIs. A condom should also be used to protect against sexually transmitted infection transmission.

  • Some hormonal side effects are possible in a small proportion of users such as: acne, bloating, mood swings, appetite increase and headaches.

  • Mirena® IUD can increase the risk of benign ovarian cysts (Kyleena® has less risk of benign ovarian cysts than Mirena®)

Who is able to use a Hormonal IUD?

Women of all age ranges are ideally suited to use a hormonal IUD.

As it is a progesterone-only method, it is suitable for women who have medical reasons why they cannot use oestrogen containing contraceptives.

The implant can be used by breastfeeding mothers as the IUD does not interpret milk supply and is safe to use in the postnatal period.

IUDs do not have interactions with other medications.

Who should not use a hormonal IUD?

There are very few reasons why a hormonal IUD would not be suitable.

It should not be used in women who are pregnant or suspected to be pregnant, those with a known malformation or structural abnormality of their uterus, those with an active pelvic infection and women with hormonally sensitive cancers.

What should you talk to your doctor about?

You should talk to your doctors about whether the IUD is suitable for you. You may also wish to ask advice about which device to choose or options for pain relief during the insertion.

At Clinic 66, you can now have your initial suitability consultation by telehealth... so you don't have to go to the clinic before your IUD insertion.

How do I get a hormonal IUD?

A consultation is performed first to make sure that the Hormonal IUD is the best choice of contraceptive for you and to make sure that there are no medical contraindications.

You may be asked to have some pre-insertion investigations such as a pelvic ultrasound or a STI check.

Once the preparation has been done, the actual insertion process only takes a few minutes but you may have to stay at the clinic to be monitored for a short while afterwards.

The insertion process requires a vaginal speculum examination, and for the size and shape of the uterus to be assessed and measured before the IUD is inserted. This can cause some cramping pains and some women prefer a local anaesthetic to help with the discomfort.

What to expect after insertion

There may be some minor side effects as your body adjusts. These may include some bleeding, spotting or cramps. Over-the-counter pain relief and heat packs are recommended solutions.

It is also recommended to avoid having sex, inserting tampons, going swimming or taking baths for two days after the procedure as these can greatly increase the risk of infection. After two days, you can resume all normal activities.

A follow-up appointment with your doctor four to six weeks after the device is put in is

recommended, but you should return sooner if you have side effects that you feel are not normal

Things to know when you have a hormonal IUD

It’s important to check the threads each month after your period as they can move. The device only works if those threads stay in the right place.

Keep a record of when you got your IUD (especially if you change doctors) and return to your doctor immediately if you have any sudden or unusual symptoms. These can include deep physical discomfort during sexual activities.

Removal of the hormonal IUD

When you are ready to remove the hormonal IUD, it can be removed simply by a doctor with a pair of forceps during a speculum examination.

The procedure is quick and relatively painless.

A new IUD can be inserted as a replacement if desired.

More information:

If you have follow-up questions or a specific query that the information on this page did not cover, we encourage you to contact us via the contact form at the bottom of this page or via phone on 02 9411 3411 or via email at online@clinic66.com.au

We can conduct an initial 'suitability' consultation via telehealth to ensure that a hormonal IUD is right for you before you book your insertion. Select "IUD Assessment" when you book your appointment.

Or you can book an appointment at our Chatswood clinic between 8 am and 6 pm, Monday to Saturday.

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