A concerning new discovery by scientists indicates that contraceptives, even low-dose ones, may boost a person’s risk of developing breast cancer. Scientists found a link between birth control pills and breast cancer years ago, but experts wondered if lower-dose pills might be a little bit safer.

Unfortunately, the new research suggests that they may not be safer at all for women based on data from around 1.8 million women younger than 50. About 60 percent of the women used some type of hormonal contraception, while the remainder did not use this type of contraception or any contraception at all.

Over 11 years, 11,517 women came down with breast cancer, and those who used hormonal contraception were 20 percent more likely to get breast cancer, a statistically significant increase. They also found that the longer women used this contraception, the more their risk increased.

“Little is known about whether contemporary hormonal contraception is associated with an increased risk of breast cancer,” reads the abstract of the paper, published in the New England Journal of Medicine. “We assessed associations between the use of hormonal contraception and the risk of invasive breast cancer in a nationwide prospective cohort study involving all women in Denmark between 15 and 49 years of age who had not had cancer or venous thromboembolism and who had not received treatment for infertility. Nationwide registries provided individually updated information about the use of hormonal contraception, breast-cancer diagnoses, and potential confounders.”