Symptoms of menopause may include hot flashes, sleeplessness, and vaginal dryness. However, some studies have shown increases in endometrial cancer risk with the combined regimens if progestins are used for less than 10 days per month. This study found that women taking the estrogen-progestogen combination had a greater reduction in risk of a major coronary event compared with women who used estrogen alone. The HERS study was the first randomized, controlled trial to look at HRT and heart disease directly. Postmenopausal osteoporosis is characterized by decreased bone mass, deterioration of bone tissue, and high bone fragility, making bone fractures of great concern.
Estrogen deficiency is the most common risk factor for osteoporosis in women.
Estrogen, with and without progestin, has been seen to be a protective and effective treatment against osteoporosis. Over the last 25 years, numerous studies have examined the possible relationship between HRT and breast cancer. Some of the studies showed an increased risk while others did not. A recent re-analysis of over 90 percent of breast cancer studies throughout the world showed an increased risk in breast cancer for women who used HRT for five years or longer. Both groups of hormone users had a higher risk of breast cancer than non-users.