HRT pills raise blood clot risk by 60 per cent even at low doses, major Danish study warns

From the Newshound archive · first published 24 September 2026.

A large Danish study covering more than one million women has found that oral HRT pills raise the risk of venous thromboembolism — clots forming in the legs and lungs — by 60 per cent, a danger that persists regardless of dose or duration of use. Researchers from North Zealand hospital calculated that for every year a woman takes the pill form of HRT, one additional woman in every thousand develops a serious clot; high doses taken for over a year were also linked to a 40 per cent greater risk of heart attack and a 50 per cent greater risk of stroke. The findings appear in The BMJ and carry particular weight given that a record two million women were prescribed HRT in England in 2025/26.

Crucially, HRT patches, gels and sprays carry no equivalent blood clot danger, meaning women can switch to safer transdermal alternatives.

Experts urge women currently on oral HRT to discuss switching to patches or gels with their GP at their next appointment.