Hormone replacement therapy (or HRT) is the use of synthetic or natural female hormones to make up for the decline or lack of natural hormones produced in a woman's body. HRT is sometimes referred to as Estrogen replacement therapy because the first hormones that were used in the 1960s as medication were estrogen compounds. HRT has two primary purposes: preventive treatment against osteoporosis and heart disease; and relief of physical symptoms associated with menopause.

Menopause is defined as the last spontaneous menstruation after which no further spontaneous menses occurs in the following years. Women who have had their ovaries removed surgically are said to have undergone surgical menopause. The exact time of menopause differs from woman to woman. Some women begin menopause at around 40 and others as late as age 55. It is a gradual transition and can take as many as ten years for...