Progestogen-only contraceptives confer a similar increased risk of breast cancer as combined oral contraceptives, according to UK and Australian researchers.

Their study involving nearly 28,000 women suggests all progestogen-only preparations — including injectables and IUDs — are associated with a “significant but comparatively small” 23-32% elevated likelihood of incident invasive breast cancer.

This risk was almost identical to that seen among those prescribed the combined pill, the team from the University of Oxford and the University of Adelaide found.

But they say the effect is transient, with the excess risk over 15 years following five years of use reaching a maximum of about 265 cases per 100,000 women.