July 28, 2014 — The use of levonorgestrel-releasing intrauterine devices (IUDs), such as Mirena, have been linked to a 19% increased risk of breast cancer, according to a study published in Obstetrics & Gynecology.
Results were based on data from about 94,000 women in Finland who used a levonorgestrel-releasing IUD between 1994 and 2007. All of the women were between the ages of 30-49 and were using the IUD to treat menorrhagia (heavy menstrual bleeding).
During the study, 2,781 women were diagnosed with cancer. Researchers concluded that levonorgestrel-releasing IUDs actually decreased the risk of many types of cancer, including:
- 50% lower risk of endometrial cancer
- 40% lower risk of ovarian cancer
- 50% lower risk of pancreatic cancer
- 32% lower risk of lung cancer
However, women on levonorgestrel-releasing IUDs were 19% more likely to be diagnosed with breast cancer than women in the general population of Finland.