A lot of women who are losing hair do so as part of thyroid problems. This is easy to fix. Hormonal fluctuations—going on birth control pills, coming off them, getting pregnant, giving birth, nursing—can cause hair loss as well. And sudden stresses can do it, too.
Wrote a couple private replies, but thot I would put my experience and recommendation out there.
A couple years ago, my hair dresser found a bald spot on top of my head. Ugh! Wow shock! Initially, I thot it was just over brushing, etc.; however, the spot did not go away with changing the hair style. Not sure if it was stress related or hormonal (did not think it was genetic), but the bald spot it was there...
Of all the health issues I thought I would have to deal with, balding was not one of them—as a girl, teen, and young woman, I had hair that was too thick for some hair styles and accessories.
Anyway, I tried Nioxin shampoo and scalp products and they worked. I gave some to my son who was starting to have thinning hair/spot on top—tho that may have been from his dad who is bald, and it worked for him as well.
Highly recommend Nioxin shampoo :)