Risks and benefits of menopausal hormone therapy

TLDR

• For most women with menopausal symptoms the benefits of menopausal hormone therapy (MHT) outweigh the risks especially when started within the first 10 years of the final menstrual period (menopause) and under the age of 60 years. 
• Transdermal preparations (patches and gels) have a reduced risk of blood clots (venous thromboembolism)
• Micronised progesterone (Prometrium) and dydrogesterone (in Femoston) may be associated with lower risks of breast cancer and blood clots compared with other progestogens 
• There is no evidence of increased breast cancer risk with the use of vaginal oestrogen (Vagifem and Ovestin) and in general they can be used safely post breast cancer with the agreement of the patient’s oncologist. 
• The only indication for preventive treatment with MHT is for the prevention (and treatment) of osteoporosis 
• Currently, MHT is not recommended for the primary prevention of cardiovascular disease or dementia, although the research data are looking promising in this area

The US Preventive Services Task Force examined 18 clinical trials for women on MHT and reported reductions in the risk of osteoporotic fractures, diabetes and colon cancer. 

Risks of breast cancer and MHT (or HRT)

The risks of breast cancer with MHT are very low especially with oestrogen only menopause hormone therapy where there may be no risk.  The risk is increased with longer duration of use, particularly in women over the age of 60 years  This is the reason why generally MHT is not initiated after the age of 60 years although the safety profile is so reassuring that there is no upper age to cease MHT and it can be continued indefinitely with the agreement of the woman with her health care practitioner and with annual review.  

See the Women’s Health Concern infographic for a comparison of lifestyle risk factors versus Hormone Replacement Therapy (HRT) treatment.  

MHT and Cardiovascular disease 

There is no evidence of harm from cardiovascular disease for women commenced on MHT close to the menopause and in fact there is a trend toward reduced risk for these women.  A Cochrane review has found that for women who started MHT within 10 years post menopause there was evidence of a degree of protection from heart disease.  The use of MHT for primary prevention of cardiovascular disease is not yet recommended pending further research.