Intrauterine System (IUS)


An Intrauterine System (IUS), (not to be mistaken for an IUD) is a small T shaped device made from plastic that sits inside the womb, it contains the hormone progesterone.

It can protect against pregnancy and lasts for between 3 to 5 years - depending on the brand.

Like all contraceptive methods other than condoms, the IUS does not protect against sexually transmitted infections.

The Intrauterine System (IUS) works in multiple ways, it releases progesterone, which thickens the mucus in the neck of the womb making it hard for sperm to get past.

Progesterone can also stop an egg being released from the woman’s ovary, and It also prevents a fertilised egg from implanting itself in the womb.

The IUS is over 99% effective when inserted correctly, meaning less than 1 in every 100 women who use an IUS become pregnant over a 1 year period.

You should visit your doctors surgery or sexual health clinic and ask about having an IUS fitted. You can find your nearest sexual health clinic here.

Normally an IUS can not be fitted until 4-6 weeks after giving birth, this means you will need to use an alternative contraception from 21 days after the birth of your baby up until you have the IUS fitted.

  • Works for 3 to 5 years
  • One of the most effective contraceptives
  • You don’t need to remember to use contraception for at least 3 years
  • Can be inserted at any time during the menstrual cycle as long as you are not pregnant
  • Can be taken out at any time (by a doctor or nurse)
  • Does not interrupt sex
  • Can be used if breastfeeding
  • Not affected by other medicines
  • You can get pregnant straight away after it is removed
  • Small risk of getting an infection after it has been fitted
  • Periods can become irregular or even stop completely
  • Small risk that your body may push out the IUS or it could move, ask your doctor or nurse how to check that it remains in place
  • May experience breast tenderness and headaches after having the IUS fitted
  • May experience acne having the IUS fitted
  • May experience changes in mood and libido
  • Does not protect against sexually transmitted infections (STIs)