Low hormone levels in women usually refers to the loss of estrogen and testosterone once a woman reaches menopause. According to WebMD, low testosterone levels may cause a drop in libido and low estrogen levels may cause hot flashes, night sweats, vaginal dryness or itching and loss of sex drive. Low estrogen levels also put a woman at an increased risk for heart disease, stroke, osteoporosis and fractures.
Estrogen is actually three hormones, which are estriol, estradiol and estrone. Only estrone remains after a woman enters menopause, according to WebMD. There are other causes of low estrogen levels in women, including hypogonadism, hypopituitarism, pregnancy failure, polycystic ovarian syndrome, anorexia nervosa, extreme exercise or training and some prescription medications, such as clomiphene. Both estrogen and testosterone replacement therapy can alleviate the symptoms associated with low levels of these hormones, but there are risks associated with replacing these lost hormones with synthetic ones. Both may increase the risk of heart disease, while testosterone replacement therapy may cause liver disease and estrogen replacement therapy may cause stroke, blood clots and breast cancer, according to the Mayo Clinic. Additionally, women who have breast or uterine cancer should not have testosterone replacement therapy, according to WebMD.