Research by Oxford University has shown that any type of hormonal contraceptive may increase the risk of breast cancer by 25 per cent.

Researchers analysed data from nearly 10,000 women under the age of 50 who had developed breast cancer between 1996 and 2017.

The records of more than 18,000 closely matched women without breast cancer were also studied.

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All forms of hormonal contraception – including the pill, the implant or an intrauterine device – were found to increase the risk of breast cancer between 23 and 32 per cent.

Gillian Reeves, professor of statistical epidemiology and director of the Cancer Epidemiology Unit, University of Oxford, said: “I don’t really see that there’s any indication here to say that women need to necessarily change what they’re doing.”

She added: “Yes, there is an increase here, and yes, nobody wants to hear that something that they’re taking is going to increase their risk for breast cancer by 25 per cent.

“The main purpose of doing this research was really to fill a gap in our knowledge.

“We’ve known for many years that combined oral contraceptives, which women have been using for decades, also have an effect on breast cancer risk, a small increase in risk which is transient.

“We weren’t absolutely sure what the corresponding effect of these progestogen-only contraceptives would be.

“What we’ve shown is that they’re just the same in terms of breast cancer risk, they seem to have a very similar effect to the other contraceptives, and the effect that we’ve known about for many years.

“I suspect that if women were prepared to accept those risks in the past, in return for the many benefits of taking hormonal contraceptives, then they may well be prepared to carry on doing that.”

In their study, the researchers looked at the absolute excess risk - the additional number of women who would be expected to develop breast cancer in those who used oral contraceptives compared with those who did not.

The researchers looked at the absolute excess risk over a 15-year period in women with five years use of oral contraceptives.

In women from the age of 16, some 84 per 100,000 non-users were likely to get breast cancer, while for five years of oral contraceptive use from age 16-20, the 15-year risk is 92 per 100,000 – resulting in an excess risk of eight per 100,000.

This jumped to an excess risk of 61 per 100,000 for users aged between 25 and 29, and 265 per 100,000 for users aged between 35 and 39.