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Intrauterine System (IUS)

A small, flexible T-shaped plastic device is put into the uterus where it releases the hormone progestogen.

This stops ovulation, thickens cervical mucus and thins the lining of the uterus to prevent pregnancy.

The IUS is over 99% effective



  • Works for 5 or 6 years depending on the type, but can be removed sooner
  • Bleeding usually becomes lighter, shorter, less painful, or may stop
  • Don’t have to think about contraception for as long as it lasts
  • Fertility returns immediately once it is removed, with no long-term effects
  • No link to weight gain
  • Not affected by diarrhoea and vomiting, as not absorbed by the tummy


  • May cause irregular bleeding/spotting, especially in the first 6 months
  • Small risk of getting an infection after it is fitted
  • Small risk of perforation
  • Some women find the insertion procedure uncomfortable, causing bad period type pains
  • No protection against STI’s


  • You are taught to check the IUS is in place
  • Not affected by other medicines
  • If fitted at or after age 45; certain IUS’s can stay in place as contraception until the menopause

Further Information: