Hormonal birth control raises risk of breast cancer — study

A new study published on Tuesday has found that all hormonal contraceptives slightly elevate the risk of developing breast cancer.

This included popular progestogen-only pills, according to a study published in the peer-reviewed PLOS Medicine journal.

What were some of the key findings?

The study found that the risk of women developing breast cancer was about the same for hormonal contraceptives that used both estrogen and progestogen as for those just using progestogen.

Researchers carried out a study involving nearly 10,000 women under 50 years of age with breast cancer, to assess the link between the recent use of hormonal contraceptives and the risk of breast cancer.

The findings suggested a relative increase of around 20% to 30% in breast cancer risk linked to the current or recent use of oral or progestogen-only contraceptives.

The study found that women taking hormonal contraceptives over a five-year period between the ages of 16 to 20 represented eight cases of breast cancer per 100,000. Women aged between 35 and 39 years old represented 265 cases per 100,000.

"What we're talking about here is very small increase in absolute risk," Gillian Reeves, who is a professor of statistical epidemiology at the University of Oxford and a co-author of the study pointed out.

"These increases in risk for breast cancer have to, of course, be viewed in the context of what we know about the many benefits of taking hormonal contraceptives," she added.

The study concluded that the absolute excess risk associated with the use of either type of oral contraceptive was estimated to be smaller among women who use them at younger rather than at older ages.