The recommendations regarding hormone replacement therapy (HRT) for menopause have gone through a very confusing transition over the past decade. Those recommendations have changed from strongly encouraging HRT, to strongly discouraging it, to now somewhere in between.
The current thinking on HRT
Most women on HRT take both oestrogen and a synthetic progestin/progestogen. The progestin is added because oestrogen alone causes the lining of the uterus to grow excessively, thus increasing the risk of uterine cancer. Adding progestin reduces the excess risk of uterine cancer, but a better protection is bioidentical natural progesterone which sadly does not occur unless women supplement separately. Currently in women who have had their uterus removed HRT will consist of oestrogen alone which gives rise to oestrogen dominance symptoms, again which can be alleviated with bioidentical natural progesterone.
Originally it was thought that HRT would protect women from heart disease. This assumption followed from two observations. First, the incidence of coronary artery disease in women rises substantially after oestrogen levels fall during menopause. Second, using HRT in menopausal women causes a favorable change in cholesterol levels and in other cardiac risk factors. So, doctors thought, the drop in oestrogen which accompanies menopause was contributing to the development of CAD in older women; replacing oestrogen (with HRT) should help to prevent CAD. And for many years HRT was widely recommended and used in menopausal women.
But then, early in the last decade, this was greatly disrupted by data from the Women’s Health Initiative (WHI) study which showed that women who received HRT with oestrogen and progestin actually had a significantly higher risk of heart attacks and strokes, as well as an increase in blood clots and breast cancer. Women who were able to receive estrogen-only HRT did not have an increase in heart attacks or breast cancer, but had an increase in strokes and blood clots.
Why Does HRT Have To Be Temporary?
HRT should be avoided in any woman who has had breast cancer, CAD, heart attack, stroke, or blood clots. The hormones used in HRT increase the risk of breast cancer. It looks like it takes about 10 years of therapy with oestrogen alone to produce an increase in breast cancer, but only five years or so for the combination of estrogen and progestin to bump up the risk of breast cancer.
So virtually all experts recommend that, if HRT is to be used, it should be used for less than five years.