|Classification and external resources|
Hypoestrogenism, or estrogen deficiency, refers to a lower than normal level of estrogen, the primary sex hormone for women. In general, lower levels of estrogen may cause differences in the breasts, genitals, urinary tract and skin.
Hypoestrogenism is most commonly found in women who are postmenopausal, have premature ovarian failure, or are suffering from amenorrhoea; however, it is also associated with hyperprolactinaemia and the use of Gonadotropin-releasing hormone analogs in treatment of endometriosis. Additionally, it has also been linked to scoliosis and young women with type 1 diabetes mellitus.
Presentations of depressed estrogen levels include hot flashes, headaches, and lowered libido. Reduced bone mass density leading to secondary osteoporosis and atrophic changes such as pH change in the vagina  is also linked to hypoestrogenism. Low levels of estrogen can lead to dyspareunia and limited genital arousal because of changes in the four layers of the vaginal wall. Hypoestrogenism is also considered one of the major risk factors for developing uncomplicated urinary tract infections(UTI) in post menopausal women who do not take hormone replacement therapy.
In patients under long-term therapy, small amounts of estrogens could be given back (“add-back regimen”) through estrogen cremes, estrogen rich foods and supplements to combat such side-effects and to prevent bone wastage. Though long-term patients, both male and female, tend to undergo annual DEXA scans to appraise bone density.
See also 
- Sartori, Feldner, MG, PC, et al. "Sexual steroids in urogynecology.". Sexual steroids in urogynecology. PubMed. Retrieved November 11, 2011.
- Lara, Useche, LA, B, et al. "The effects of hypoestrogenism on the vaginal wall: interference with the normal sexual response.". The effects of hypoestrogenism on the vaginal wall: interference with the normal sexual response. PubMed. Retrieved November 11, 2011.
- Gonadotropin-releasing hormone agonist-induced hypoestrogenism and blood flows in cerebral arteries.