Hormonal IUD linked to increased breast cancer risk, warns researcher in study from Denmark

When choosing a contraceptive method, many women prefer the hormonal IUD. However, this popular choice, designed to prevent pregnancy, is linked to a serious side effect—an increased risk of breast cancer. Senior researcher Lina Mørch explains that the decision ultimately depends on individual needs and whether one accepts this risk.

Mørch is leading a peer-reviewed study conducted by the Cancer Research Center that found that among 10,000 women using a hormonal IUD for five years, there’s an increased incidence of 14 cases of breast cancer compared to a control group of 10,000 women not using hormonal contraception. The study tracked 157,190 women aged 15 to 49 over 15 years, with 78,595 using hormonal IUDs.

The research focuses specifically on the Mirena IUD, which has a higher hormone dosage compared to other lower-dose IUDs like Jaydess and Kyleena. While it highlights increased risks, it does not confirm that the IUD directly causes breast cancer. Various other factors, such as pill use, smoking, and obesity, were also considered.

The risk for women under 30 is deemed “extremely low,” according to Mørch, making the findings irrelevant for younger women. In contrast, those over 30 may want to consider alternative contraceptive options as the risk increases with age and duration of IUD use.

The study indicates that the breast cancer risk associated with hormonal IUDs is comparable to that of the birth control pill, which has previously been linked to increased risks of depression and breast cancer.

Given this information, Mørch urges that the decision about contraceptive methods should be made based on personal needs and a risk assessment that encompasses all lifestyle factors.