A new study has revealed the possibility that a pill used to prevent pregnancies could also cause breast cancer to develop in some women.

Published by the journal Cancer Research, the study has found that birth control pills with high levels of estrogen have a higher risk of giving women breast cancer, according to the Toronto Sun.

"Our results suggest that use of contemporary oral contraceptives in the past year is associated with an increased breast cancer risk relative to never or former oral contraceptive use, and that this risk may vary by oral contraceptive formulation," researcher Elisabeth Beaber, who works with the Fred Hutchinson Cancer Research Center, said.

The Center conducted the research, examining health records and oral contraceptive use among 1,102 women aged between 20 and 49 who had breast cancer and 21,952 women without the disease but in the same age group, according to CBS News.

This study, unlike previous ones that relied on self-reports by women, utilized electronic pharmacy records of medicine brands, dosages, and duration of medical use, reports CBS News. This led to the conclusion that high levels of estrogen in birth control pills could lead to breast cancer.

"The use of high-dose estrogen pills was related to a 2.7-fold increase in breast cancer risk, and the use of moderate-dose estrogen was linked to a 1.6-fold increase. Pills containing ethynodiol diacetate were related to a 2.6-fold higher risk. Triphasic combination pills containing an average of 0.75 milligrams of norethindrone increased the risk 3.1-fold," explains CBS News.

According to Medical News Today, "women who were recent users of oral contraceptives -- defined as completing at least one prescription for the pills in the past year -- had a 50% increased risk of breast cancer, compared with former users and those who had never used them."

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