All hormonal contraceptives carry a slightly increased risk of breast cancer, including the increasingly popular progestogen-only pill, a study published Tuesday found.

Previous studies have found an increased risk of breast cancer from dual-hormonal or combined contraceptives that use both estrogen and progestogen. "Science Alert" (Science Alert).

Although the use of progestogen-only contraceptives has been on the rise for more than a decade, little research has previously been conducted on their association with breast cancer. The study, published in the journal PLOS Medicine, found that the risk of developing breast cancer in women is about the same for hormonal contraceptives that use both estrogen and progestogen as for those that use only progestogen.

According to the study, women who use hormonal contraception have a 20 to 30 percent higher risk of developing breast cancer than those who do not. The findings are similar to those published previously, including a large 1996 study.

The study also confirmed, like others, that the risk of breast cancer decreases in the years after a woman stops using hormonal contraception.

Stephen Duffy, a professor at Queen Mary University of London who was not involved in the study, described the findings as "encouraging because the effect is modest".

The study included data from almost 10.000 women aged under 50 who developed breast cancer between 1996 and 2017 in the UK, where the use of progestogen-only contraceptives is now as widespread as the combined method.

Gillian Reeves, professor of statistical epidemiology at Oxford University and co-author of the study, said there are several explanations for the increasing use of progestogen-only contraceptives. They are recommended for women who are breastfeeding, who are at risk of cardiovascular problems or smokers over 35 years of age.

"Maybe it's just because women are now probably taking hormonal contraception later in life," Reeves said. "So they are naturally at greater risk than those other conditions for which the risk is increased with combined contraceptives," she concluded.

"No one wants to hear that something they're taking will increase their risk of breast cancer by 25 percent. We are talking about a very small increase in absolute risk here. These increases in breast cancer risk must, of course, be seen in the context of what we know about the many benefits of taking hormonal contraceptives. "Not only in terms of birth control, but also because we know that oral contraceptives actually provide significant and long-term protection against other types of cancer in women, such as ovarian cancer and endometrial cancer," said Jillian Reeves.