Women who opt to use Mirena or a similar IUD as their preferred method of birth control may be unknowingly increasing their risk for breast cancer, a new study suggests.

The research was recently published in the journal of Obstetrics & Gynecology, and involves the levonorgestrel-releasing intrauterine system, which belongs to a class of IUDs that includes Mirena, a birth control implant marketed by Bayer Healthcare Pharmaceuticals, and Plan B, also known as the morning-after pill. According to the journal, researchers from the Department of Obstetrics and Gynecology in Finland saw an increase in the number of women between the ages of 45 and 49 who were diagnosed with breast cancer, compared to those not exposed to this type of contraceptive. The study involved more than 93,000 Finnish women aged between 30 and 49 who were exposed to an IUD to treat heavy menstrual bleeding from 1994 to 2007.

60% of IUDs in Finland Used for Heavy Menstrual Bleeding

Between those years, at least 60 percent of all LNG-IUSs sold in the country were used for this purpose, rather than contraception. A similar trend was seen in the U.S., when the U.S. Food and Drug Administration (FDA) expanded Mirena’s list of approved uses in 2009 to include the treatment of heavy menstrual bleeding. The IUD originally received market approval as a contraceptive nine years earlier.

“The number of diagnosed new breast cancer cases among Finnish women who used LNG-IUS for menorrhagia was 19% higher than in Finnish general population,”  said a lead author of the study, who later mentioned that these findings are the first to associate IUDs with breast cancer.

The findings of this recent study are already making waves in the U.S., and should make women and their doctors mindful of side effects that may stem from use of Mirena and other contraceptives.

“It’s a great reminder that we need to weigh the benefits of some of these methods against the risks,” said the director of Comprehensive Women’s Health in Silver Spring, Maryland.

An increased risk for breast cancer is hardly the only serious side effect associated with IUDs. According to more than 1,300 Mirena lawsuits filed in the U.S., this particular device can spontaneously migrate away from the uterine wall, perforating the uterus and resulting in a host of serious complications.

Pursue a Mirena Lawsuit

Women who allegedly experienced complications caused by the Mirena IUD may be eligible to pursue a claim against Bayer. Call the Firm at (877) 779-1414.

Published July 9, 2014 by