http://www.webmd.com/skin-problems-and-treatments/hair-loss/features/women-hair-loss-causesAnd this is a very good article (extract below) --
http://www.nbcnews.com/id/14342447/site/todayshow/ns/today-today_health/t/getting-root-female-hair-loss/#.URh5omd168AWhat causes a change in this hair loss/ hair growth process?
If lots of hair begins to fall out throughout the scalp, it’s obviously due to a change in the normal hair cycle: either a short anagen phase or an increase in the number of follicles that enter the telogen phase. When the majority of hair follicles “go telogen” it’s called telogen effluvium or stress alopecia. A shock to the body’s system, which stresses the hair follicles, is often to blame for this change in cyclical hair events. Two to three months after the stressor hits, up to 70 percent of hairs can enter the telogen phase and commence a massive “fall out”. There are a number of shocks that are known to cause this. They include:
A sudden hormone change (usually a drop in hormone levels)
After the birth of a baby ( delivery of the placenta causes the levels of pregnancy hormones to plummet)
Discontinuing birth control pills or hormone replacement therapy
High fever
Acute trauma (surgery, physical injury or psychological trauma)
Severe dieting ( inadequate protein and iron intake)
Underactive or overactive thyroid
Diseases such as diabetes and lupus
Chemotherapy
Medications: These include retinoids, blood pressure medication, anti-depressants, certain birth control pills and even NSAID’s (including Ibuprofen)
Burns or radiation therapy
Note with stress alopecia, the loss over the scalp is general, not patchy and hair loss on other parts of the body can also occur. You and your doctor may be able to ascertain if your hair loss falls in the category of stress alopecia by simply running your fingers through your hair and seeing if the many hairs that are shed have clubbed shafts.
Are there other tests that should be done to diagnose telogen effluvium?
Your doctor may want to check your iron and thyroid levels, but in most cases, your history is the most important factor for diagnosis.
What is the therapy for this type of hair loss?
Mostly reassurance. If the loss is due to a birth, illness, or a self-limited problem, it will stop and will not progress to baldness. New hair shafts will come in and in a few months the hair loss will diminish. Eventually the hair will grow back and become normal. Obviously if the loss was due to a medication, the drug should be stopped. (Note: If it was due to chemotherapy the course should be completed and hair growth will subsequently return.)
If iron levels are low, iron should be supplemented (after making sure that the cause was not abnormal bleeding, which could be a sign of a serious disorder), and if the thyroid level is “off,” this should be treated.
