Muscle and bone
There is a significant decrease in hip fracture risk during treatment that to a lesser degree persists after HRT is stopped. It also helps collagen formation, which in turn improves intervertebral disc and bone strength.Hormone replacement therapy in the form of estrogen and androgen can be effective at reversing the effects of aging on muscle. Lower testosterone is associated with lower bone density and higher free testosterone is associated with lower hip fracture rates in older women. Testosterone therapy, which can be used for decreased sexual function, can also increase bone mineral density and muscle mass. Side effects
Side effects in HRT occur with varying frequency and include:

Contraindications
The following are absolute and relative contraindications to HRT:

Absolute contraindications
Undiagnosed vaginal bleeding
Severe liver disease
Pregnancy
Severe coronary artery disease
Aggressive breast, uterine or ovarian cancer

Relative contraindications
Migraine headaches
History of breast cancer
History of ovarian cancer
Venous thrombosis
History of uterine fibroids
Atypical ductal hyperplasia of the breast
Active gallbladder disease (cholangitis, cholecystitis)
Well-differentiated and early endometrial cancer – once treatment for the malignancy is complete, is no longer an absolute contraindication. History and research
The extraction of CEEs from the urine of pregnant mares led to the marketing in 1942 of Premarin, one of the earlier forms of estrogen to be introduced. From that time until the mid-1970s, estrogen was administered without a supplemental progestogen. Beginning in 1975, studies began to show that without a progestogen, unopposed estrogen therapy with Premarin resulted in an eight-fold increased risk of endometrial cancer, eventually causing sales of Premarin to plummet.
Clinical medical practice changed based upon two parallel Womens Health Initiative (WHI) studies of HRT. Prior studies were smaller, and many were of women who electively took hormonal therapy. One portion of the parallel studies followed over 16,000 women for an average of 5.2 years, half of whom took placebo, while the other half took a combination of CEEs and MPA (Prempro). This WHI estrogen-plus-progestin trial was stopped prematurely in 2002 because preliminary results suggested risks of combined CEEs and progestins exceeded their benefits. The first report on the halted WHI estrogen-plus-progestin study came out in July 2002.Initial data from the WHI in 2002 suggested mortality to be lower when HRT was begun earlier, between age 50 to 59, but higher when begun after age 60. In older patients, there was an apparent increased incidence of breast cancer, heart attacks, venous thrombosis, and stroke, although a reduced incidence of colorectal cancer and bone fracture. At the time, The WHI recommended that women with non-surgical menopause take the lowest feasible dose of HRT for the shortest possible time to minimize associated risks. Some of the WHI findings were again found in a larger national study done in the United Kingdom, known as the Million Women Study (MWS). As a result of these findings, the number of women taking HRT dropped precipitously.