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IUS vs IUD: Which Is The Best Contraceptive?

Published : Thursday March 3, 2016 | Posted in : Contraception

Look out! It's battle of the IUS and the IUD here. Which is best, what risks are there, and what might suit you? Let's take a look.

What is an IUS?

IUS stands for intrauterine system. It's a small T-shaped plastic device that releases the hormone progesterone. Two threads hang from the IUS down through the vaginal opening. It's placed into the uterus by a professional.

What is an IUD?

IUD stands for intrauterine device. It's similar to an IUS but is made of plastic and copper. Instead of releasing hormones it prevents sperm surviving in the uterus or implanting in the womb. It's sometimes called a coil.

So the difference is...?

In short, an IUS is a plastic device that releases progesterone and the IUD is a plastic and copper device that doesn't release hormones.

Here are the specific comparisons:


The IUS is over 99 percent effective. The newer IUDs have more copper and are 99 percent effective. So we'll call that a draw.

Ease of use

Both the IUS and the IUD must be fitted by a trained nurse or doctor. Once they are in place there's nothing to do other than check for the threads each month. If you can't find them, make an appointment with whoever fitted the device.

The IUD is better for women intolerant of or unhappy with hormones in their body. If you can't take the pill or the implant, the IUD might solve your problems. Lack of hormones means the IUD wins on ease of use.

Long-term fertility effects

With both the IUS and the IUD, your fertility will return following removal.

Another draw. This is going to be close.

Effect on periods

The IUS usually makes periods lighter and shorter. They may stop totally after a year or so of use. Some women have the IUS simply to help with painful and heavy periods.

The IUD may cause periods to get heavier, more painful and potentially longer, although this tends to improve after a few months. There may be breakthrough spotting in the first six months too.

That's a win for the IUS.

How long do they last?

The IUS comes in two varieties - the Jaydess and the Mirena. The Jaydess is smaller, has less progesterone and lasts for three years. The Mirena lasts for five years. The IUD can work for five to ten years depending on the type.

It's a win for the IUD on length of time before getting pulled about by the nurse.

The risks


There's a small risk of infection after an IUS is fitted.

It's not common but an IUS can be expelled by the uterus or dislodged, that's why it's important to check the threads each month. The IUS may also perforate the uterus when it's fitted. The risk is small but surgery may be required to remove it.

If the IUS fails there's a risk that you may experience an ectopic pregnancy - that's when a fertilised egg implanted in the fallopian tubes.

There's a chance you might be intolerant of progesterone, though this is true of any hormonal contraceptive.

And the IUD?

Exactly the same except there are no hormones; instead a few women find they are intolerant to the copper content.

Oh dear - another draw.

Overall Winner – IUS


It's a close call but overall it looks like the IUS is our winner.

That's not to say it's the most suitable for you though. Talk over your choices with your doctor to choose the best fit.


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