Hair loss in women is a serious condition with lots of conventional explanations. One area that's never mentioned is the connection to poor sleep quality, especially due to breathing problems at night. A significant percentage of men and women have undiagnosed sleep-breathing problems, with the end extreme being called obstructive sleep apnea.
It's estimated that about 1/4 of all men and 1/10 of all women have at lease mild sleep apnea, and 90% are not diagnosed. However, there's a variation of sleep apnea called upper airway resistance syndrome (UARS), where you'll stop breathing while sleeping, but not long enough to be called obstructive sleep apnea.
Typically these people (more typically thin women) will have colds hands or feet, prefer not to sleep on their backs, feel tired all the time, no matter how long they sleep, and will usually have at least one parent that snores heavily.
These multiple arousals lead to a chronic low-grade physiologic stress response which heightens the nervous system (and immune system). During times of stress, blood is shunted away from low-priority organs like the GI system, reproductive organs, the distant extremities and the skin. Chronic lack of blood flow can lead to a number detrimental effects, including hair loss.
It's also been shown that chronic physiologic stress also raises your cortisol levels, lowers your thyroid levels, and alters your estrogen/progesterone/testosterone balance.
There are also anecdotal reports of people who report hair regrowth after starting sleep apnea treatment.
If you have any of the symptoms mentioned above, you should get checked for UARS. In many cases, UARS progresses into obstructive sleep apnea, especially after menopause. Even if it doesn't help your hair loss, being diagnosed may prevent complications of sleep apnea, including hypertension, diabetes, weight gain, anxiety, depression, and heart disease.