Hormonal coils have become increasingly popular in recent years, but a recent study found an unexpected association between the contraceptive coil and an increased risk of breast cancer.
Although the cancer risk unearthed by the study, published last week in the journal Jama, was low overall, and extremely low for women under 30, the negative headlines are the latest example of a slew of bad PR surrounding the coils.
The coils, which release low levels of hormones into the body, are one of two types of contraceptive intrauterine device (IUD). The other is the so-called "copper" coil, which doesn't release hormones into the body.
Researchers compared nearly 80,000 women in Denmark between the ages of 15 and 49 who had used a hormonal coil for five years with the same number of similar women without a coil. Those with the coil had a 40% higher chance of developing breast cancer in terms of "relative risk", said The New York Times, although the "absolute risk" measured in extra diagnosed cases was less than 1%.
The oral contraceptive pill has long been known to have a similar risk factor, but the assumption had always been that the coil would not increase the risk because of the lower levels of hormones released. The results were "highly unexpected", Dr Channa Jayasena, from Imperial College London, told The Independent.
And they should be taken "seriously", especially by women over 30, when the risk of breast cancer increases, said Lina Morch, from the Danish Cancer Institute, who led the study. | 
