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Intrauterine System

An intrauterine system (IUS) is a form of hormonal birth control that prevents pregnancy by slowly releasing the hormone levonorgestrel into the uterus. The IUS is a T-shaped device that is intrauterine which means it is inserted into the uterus and can remain there for up to five years. 
An intrauterine system is 99.9% effective in preventing pregnancy.
IUS not available through the sexual health clinic, only prescription and referral can be provided. The IUS is available through a pharmacy. Contact your pharmacy for cost. Condoms are available at no charge at the health unit. 

How it works 

  • It thickens the cervical mucus making it difficult for sperm to reach the egg.
  • It causes changes in the lining of the uterus that helps to prevent implantation.
  • In some women, it may prevent the ovary from releasing an egg.


  • Safe, simple and convenient.
  • Provides very effective, long-lasting pregnancy protection.
  • Can be used for up to 5 years. 
  • Does not contain estrogen.
  • May stop or decrease periods.
  • May reduce period cramps.
  • May reduce your risk of certain kinds of cancer. 
The Society of Obstetricians and Gynaecologists recommend that you contact your health care provider if any of the following occur:
  • You cannot feel the IUS threads.
  • You or your partner can feel the lower end of the IUS.
  • You think that you are pregnant.
  • You experience persistent abdominal pain, fever, or unusual vaginal discharge.
  • You or your partner feel pain or discomfort during intercourse.
  • You experience a sudden change in you menstrual periods.
  • You wish to have the device removed or you want to get pregnant. 
Hormonal birth control and STIs
The IUS protects against pregnancy, not STIs or HIV/AIDS. It is best to always use a condom when having sex even if you are using birth control. Free condoms are available through the Northwestern Health Unit.