What causes female pattern hair loss?
FPHL has a strong genetic predisposition. The mode of inheritance is polygenic, indicating that there are many genes that contribute to FPHL, and these genes could be inherited from either parent, or both. Genetic testing to assess risk of balding is currently not recommended, as it is unreliable. Currently, it is not clear if androgens (male sex hormones) play a role in FPHL, although androgens have a clear role in male pattern baldness.
The majority of women with FPHL have normal levels of androgens in their bloodstream. Due to this uncertain relationship, the term FPHL is preferred to ‘female androgenetic alopecia’. The role of oestrogen is uncertain. FPHL is more common after the menopause suggesting oestrogens may be stimulatory for hair growth. But laboratory experiments have also suggested oestrogens may suppress hair growth.