The Mirena IUD is 00.9% effective against pregnancy and can be used up to 5 years continuously.

What is the Mirena IUD?

An IUD is a small device which is placed inside the uterus. The stem of this IUD contains levonorgestrel. This hormone is a progestin much like the progesterone a woman’s ovaries produce. The effective hormone level in the blood is only 5-10% that of the birth control pill and the majority of women (>75%) continue to ovulate.

How does the Mirena IUD work?

The hormone (levonorgestrel) in the IUD:

  • thickens the cervical mucus to become thicker so sperm cannot reach the egg
  • thins the lining of the uterus

How effective is the Mirena IUD? How long can a Mirena stay in place? How commonly is it used?

  • 99.9% effective against pregnancy. Among typical users who use the Mirena IUD, one in 1,000 will experience an unintentional pregnancy in the first year.
  • Mirena is as effective in preventing pregnancy as tubal sterilization and can stay in place for up to five years.
  • This method has been available for 10 years in Europe and has been used by approximately 2 million women worldwide. In Europe 10-25% of women use an IUD compared to 2% in the United States. Mirena is part of the reason for the popularity of the IUD in Europe.

What are the advantages of the Mirena IUD?

  • Mirena is the most effective reversible contraceptive method ever developed
  • Mirena decreases menstrual cramping and dramatically decreases menstrual blood loss (~90% reduction in menstrual blood loss).
  • 20% of women using Mirena stop getting monthly bleeding either soon after insertion or later on (this is safe).
  • The Mirena IUD remains highly effective for 5 years.
  • Mirena can reduce the pain of endometriosis
  • Once Mirena is removed, fertility returns rapidly. Approximately 8 out of every 10 women trying to become pregnant will become pregnant in the first year after Mirena is removed.
  • All you have to do is check for the strings each month.

What are the disadvantages of the Mirena IUD?

  • There are usually more bleeding days than normal for the first few months and less than normal after 6 to 8 months. If your bleeding pattern is bothersome, contact your physician.
  • The Mirena could fall out (called an expulsion): in ~5% of women
  • There is a 2-5% chance of hormonal side effects: headaches, acne, breast pain, moodiness.
  • There may be brief discomfort at the insertion of the device.
  • There may be in increase/change in vaginal discharge.
  • An IUD does not provide protection against sexually transmitted infections. Use condoms if there is any risk.
  • There is a high initial cost of the device, approximately$330-$360 depending on which pharmacy you purchase it form. The device is covered by most extended drug plans. The cost of the IUD itself is non-refundable, even in cases of failed insertion, expulsion, or unsuitability.

What are the risks of the Mirena IUD?

  • There is a 1 in 20 risk of the IUD being expelled, usually in the first year of use.
  • There is a 1 in 1000 risk of uterine perforation at the time of insertion.
  • There is a 1 in 100 risk of pelvic infection in the 20 days following insertion but the risk is the same as a non-IUD user thereafter.

How can I start using Mirena IUD?

  • Mirena can be inserted by a trained physician. Island Sexual Health Society (250-592-3479) runs designated IUD clinics with trained physicians. We ask potential users to get prescreened for cervical or vaginal infections at either ISHS or their family doctor before the insertion.
  • If you use condoms only, please abstain from sex from your last period until the IUD can be inserted.
  • If the risk of pregnancy can be excluded, an IUD may be inserted at any time in the woman’s cycle.
  • You can expect some strong menstrual type cramping at the time of insertion and for about 20 minutes after. The insertion itself usually takes less than 5 minutes.
  • It is convenient if someone can drive you home from the insertion appointment.
  • Be sure you are comfortable locating your cervix prior to insertion (your vagina feels like the inside of your mouth and your cervix feels like the end of your nose)

Remember that IUDs provide no protection against sexually transmitted infections. Use condoms to protect yourself and your partner.