A study published in The BMJ on 23 September 2026 has investigated a potential link between oral menopause hormone therapy and an increased risk of blood clots and cardiovascular disease, especially at higher doses.
The 'case-control' study, which involved women in Denmark, found that oral oestrogen replacement therapy was associated with an increased risk of venous thromboembolism, which includes leg vein clots. This risk was observed even with short-duration use.
For stroke or heart attack, the study indicated an increased risk only with high-dose oral oestrogen replacement therapy administered for more than one to five years. In contrast, oestrogen replacement patches applied to the skin did not show an associated increased risk.
Professor Robert F. Storey, Professor of Cardiology at the University of Sheffield, commented that the study's conclusions are well supported by its data. He noted that oral oestrogen replacement is known to stimulate the liver to increase factors that promote blood clot formation, while patches do not stimulate the liver in the same way.