Hormonal IUD (Mirena®)

WHAT IS IT?

The hormonal IUD is technically called an IUS (Intrauterine system). It is often referred to by its brand name, Mirena. It is a T-shaped device that contains a hormone called levonorgenstrel.

HOW DOES IT WORK?

The hormone inside the IUS releases slowly over time and changes the lining of the uterus, so that implantation of a fertilized egg is more difficult. It also thickens the cervical mucus, making it difficult for sperm to reach the egg. In some women, it may prevent the ovary from releasing an egg.

The Mirena can be kept in for up to 5 years. After 5 years, the hormone will have depleted to a level that no longer offers protection against pregnancy.

For more information, please visit Mirena.ca.

HOW EFFECTIVE IS IT?

The Mirena is 99.9% effective in preventing pregnancy. It does NOT offer protection against sexually transmitted infections (STIs).

WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF USING THE IUS?

ADVANTAGES:
• long-acting contraceptive; can be left in place for up to five years
• no daily contraceptive routine required
• does not contain estrogen
• does not interfere with intercourse
• regulates menstrual cycle and reduces cramps
• may be suitable for women who are breastfeeding
• may reduce pain due to endometriosis
• may lower the risk of precancerous cells developing in the lining of the uterus
• some users will stop having menstrual cycles while using Mirena

DISADVANTAGES:
• contains hormone
• possible side effects include irregular bleeding or spotting in the first months after insertion
• perforation of the uterus may occur at the time of insertion, but this is rare
• may be expelled from the uterus. This happens in 6% of IUS users
• does not offer protection against STIs
• requires a physician for insertion and removal
• some users will stop having menstrual cycles while using Mirena