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intrauterine devices (iud)

What is an IUD?

An IUD is a small, plastic T-shaped device that sits in your womb (uterus).

Some are hormonal and others are not.

IUDs stop you from getting pregnant in multiple ways.

 They can work by getting in the way of the sperm or by stopping an embryo from implanting. IUDs can also work in some other ways too.  

IUDs are a great form of birth control as they are very effective, long-lasting (up to 10 years), can have other health benefits, and if you decide you want a pregnancy or you want to stop using it - get it removed!


The risk of pregnancy is less than 1 per 100 women with typical and perfect use.

In NZ there are three different IUDs available:  

Mirena, Copper-IUD, and Jaydess


does this mean?

Doctors discuss the

effectiveness of contraception

by "perfect" and "typical" use.

This is because some methods are affected by human error: 

Perfect use:

The method is used perfectly

(no human error)

   Typical use:

Accounts for human

error (e.g. forgetting

a pill) 


How good? 

One of the best methods of birth control 

>99% effective at preventing pregnancy with typical and perfect use 

How easy? 

"Fit and forget" - insert the device, then you don't need to think about it for years!

Side effects? 

Copper IUD: increase bleeding and cramps

How hard to get? 

Appointment with your GP or Family Planning

How much?

Prescription cost ($5) 

That's $0.50 - $1 per year for birth control 

types of iud

Demonstration IUD_edited.jpg

Mirena & Jaydess

How do THEY work?

Mirena and Jaydess release a hormone locally in the womb, that has multiple effects to stop pregnancies.

They can work threefold by:

  • Thinning the lining of the womb (so the embryo can't implant)

  • Thickening cervical mucus (so sperm can't get into the womb)

  • Stopping ovulation (20% of women)


how long do they last?

  • Mirena up to 5 years

  • Jaydess up to 3 years

why would they suit me? 

Hormonal IUDs can be particularly helpful if:

  • You want something long-lasting

  • You have heavy or painful periods

  • You forget to take pills/use condoms 

  • You have epilepsy and want something long lasting

Image by Reproductive Health Supplies Coalition

NON-Hormonal Copper

How does it work? 

The copper-IUD has two main ways to stop pregnancy:

  • Irritant to sperm (stops sperm from getting to the egg)

  • Irritant to the lining of the womb (stops potential pregnancy from implanting in the womb)

How long does it last?

  • Up to 10 years

why would it suit me?

The copper-IUD can be particularly helpful if:

  • You want something long-lasting

  • You don't want to use hormones

  • You forget to take pills/use condoms 

  • You have epilepsy and want something long-lasting

what next?

You will need to book an appointment with your GP or Family Planning to ensure an IUD is the correct birth control method for you.


Once confirmed, you can proceed to have an IUD inserted by a trained professional.  

In the future...
luna health hope to provide a birth control service that assesses eligibility for each birth control method

This will save you time and money


  • Fit and forget 

  • Lasts a long time (Copper - 10 years; Mirena - 5 years; Jaydess - 3 years)

  • Easy to use 

  • Hidden (some partners say they can feel the string)

  • Suitable after having a baby (post-partum) and while breastfeeding

  • Copper IUD has no hormones 

  • Mirena IUD protects against endometrial cancer

  • Mirena IUD can reduce your period (or stop it all together!)


  • At the time of insertion

    • Infection, very low risk of uterine perforation (hole in the side of the uterus)

  • Mirena - spotting/irregular bleeding 

  • Copper - period cramps, increased bleeding

  • IUD expulsion (falling out)

Share your experience

help others decide what is best for them 

Your experience
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your experience

Avatar 102

Kim, 28

I have had a Mirena for >10 years. Each Mirena has lasted 5 years and I have NO periods (although I know some people do). I have loved my Mirena, and have had no complications or issues. I experienced slight cramping with each insertion, but so worth it!

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Anon, 28

I have had a non-hormonal IUD for nearly 5 years, and I love it! I'm quite forgetful so I love not having to worry about taking a pill, and I love that it doesn't affect the timing of my periods or mood. I have had to deal with slightly heavier periods, but overall it's totally worth it for the peace of mind.

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Sacha, 30

I have PCOS (Polycistic Ovary Syndrome) and really heavy periods. After my own research I decided to switch from the contraceptive pill to the Mirena IUD. It was painful to get in but fairly quick. I love that the Mirena is highly effective and it's 'set and forget'. I still get my period, but it's very light and cramps are minimal. It was only AFTER I made the decision to get it myself, that the Doctors and a Gynecologist told me it was the best option for me. I wish it had been discussed with me as an option earlier!

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