A new comprehensive study has revealed that long-term use of oral contraceptives is associated with a significant increase in breast cancer.
The report was published in the latest issue of the New England Journal of Medicine.
The study group was huge, involving approximately 1.8 million Danish women between the age of 15 and 49. The study found a roughly 20 percent increased risk of breast cancer among women who use some type of hormonal contraception.
The report says that the breast cancer risk increases by 9 percent if a woman takes contraceptives for a year, and up to 38 percent for women who are on the pill for 10 years or more.
"This is an important study because we had no idea how the modern day pills compared to the old-fashioned pills in terms of breast cancer risk," says Dr. Marisa Weiss, an oncologist who founded the website breastcancer.org
"Gynecologists have just assumed that a lower dose of hormone meant a lower risk of cancer, but the same elevated risk is there," Dr. Weiss observed. She says that any hormone combination strong enough to disrupt ovulation and interfere with normal menstrual cycles is enough to raise the risk of cancer.
This is far from the first research indicating that extended use of oral contraceptives exposes women to a higher risk of breast cancer.
A study released in 2014 by the American Association for Cancer Research found that the recent use of oral contraceptives increased the risk of breast cancer by 50% compared to women who had never taken the pill or were no longer on it.
Yet breast cancer is not the only health risk for women linked to contraceptive use. A South Korean study released last year showed that women who had been on the pill for even six months had an increased risk of diabetes.
A 2015 study printed in the British Journal of Medicine revealed that women who use contemporary contraceptives have a 50 percent greater chance of developing blood clots.
Guidelines issued by the American Heart Association in 2014 warned that women who use hormonal contraceptives have an increased risk of hypertension and double their risk of having a stroke.
A study released in 2013 by the American Academy of Neurology determined that women who use the contraceptive pill were 35 percent more likely to develop multiple sclerosis.
Another study released in 2016 by the University of Copenhagen found that women who used hormonal contraceptives were 40 percent more likely to develop depression within six months.