Hormone replacement therapy involves some risk
Hormone therapy (also known as hormone replacement therapy) is widely used for controlling menopausal symptoms. It has also been used for the management and prevention of chronic diseases such as cardiovascular disease, osteoporosis and dementia in older women.

This Cochrane systematic review assessed the long- term clinical effects of using hormone therapy by reviewing fifteen randomised double- blind trials involving around thirty- five thousand women altogether.

Some of the trials looked at the effects of hormone therapy with oestrogens alone, while others studied the effects of combined hormone therapy (which is made up of oestrogens and progestogens).

In healthy women, combined hormone therapy, administered on a continuous basis, significantly increased the risk of obstruction of a vein by a blood clot (venous thromboembolism). It also significantly increased the risk of fatal or non- fatal heart attack (after a year’s use), stroke (after three years’ use), breast cancer (after five years’ use), gallbladder disease, and - in women over 65 years - dementia. Long- term oestrogen alone also significantly increased the risk of stroke and gallbladder disease.

Among women with cardiovascular disease, long- term use of combined hormone therapy significantly increased the risk of venous thromboembolism and gallbladder disease.

On the whole, the benefit offered by hormone therapy was a significant reduction in the risk of fracture or colorectal cancer, but only after four or five years of treatment.

The highest risk of cardiovascular events with combined hormone therapy occurred in the first year of use.

Farquhar CM, Marjoribanks J, Lethaby A, Lamberts Q, Suckling JA, the Cochrane HT Study Group. Long- term hormone therapy for perimenopausal and postmenopausal women. The Cochrane Database of Systematic Reviews 2005, Issue 3. Art. No.: CD004143. DOI: 10.1002/ 14651858. CD004143. pub2.