Can menopausal hormone therapy prevent coronary heart disease?

Observational studies show that women who take menopausal hormone therapy (MHT) have a greatly reduced risk of coronary heart disease (CHD). But in some large randomized controlled trials, MHT failed to decrease CHD and so has been deemed inappropriate for long-term prophylaxis against atherosclerosis or other chronic diseases associated with the menopause. Despite the apparent strength of this conclusion, several recent reports suggest that MHT could be atheroprotective when started close to the menopause, and effects of early discontinuation of MHT have never been studied in randomized trials. Here, we examine these reports and highlight existing uncertainty regarding the effects of long-term continuation versus early discontinuation of early-start MHT on atherosclerosis and CHD risk. We call for new research on this question, and an evidence-based review of existing recommendations for MHT.