Intrauterine Contraception

How does it work?

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The IUS works by releasing the hormone progesterone.

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This thickens the mucus in the cervix so sperm cannot easily pass through and it thins the lining of the womb (endometrium) which makes it difficult for the egg to implant itself.

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How long does it last?

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It lasts for 3-5 years depending on the brand.

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Who can use it?

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Most women can use the IUS.

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However it may not be suitable if you have a history of*:

• Breast, cervical or endometrial cancer

• Blood clots

• Liver disease

• An untreated STI

• Pelvic inflammatory disease. 

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How effective is it?

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The IUS is approximately 99% effective.

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Advantages

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There are many advantages to using the IUS such as: 

• It is long-lasting and effective

• You do not have to remember to use it

• It can cause lighter periods

• It is an alternative to oestrogen contraceptives

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Disadvantages

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The disadvantages of the IUS include:

• Lack of prevention against STIs

• There are risks (e.g. pelvic infection, ovarian cysts and rarely damage to the womb when inserted)

• Side effects (e.g. headaches, acne, breast tenderness, mood changes)