I've heard of this. My college roommate had it, as did her sister. Their mom, actually, was almost totally bald--she wore such nice wigs, I never knew she didn't have any hair. Theirs was genetic and affected only the women in the family. My friend in college already had a small bald spot at the top of her head. So if you've managed to make it to age 42 before showing signs--I'd say you're doing pretty well.
Taking biotin or a supplement containing biotin and other important nutrients will also help you quite a bit. Whole Foods sells a supplement that is good for hair and nails that many people find very helpful. There might also be some other products that would be of benefit to you; the workers in the health section of Whole Foods are quite knowledgable and would be able to direct you to some good brands.
Sorry to hear you are going through this. Yes, childbirth is very hard on a woman's body. Many women find out they have genetic problems (like me) or hereditary problems or start having chronic illnesses (like me) after having children because their bodies are so depleted of critical nutrients, vitamins, minerals, enzymes, amino acids that their babies took from them during the 9 months they were growing inside their wombs. More than likely, like me, you have genetic/hereditary issues you didn't know about before getting pregnant, and your body was probably deficient in key nutrient areas as well, that after having your child, your body said "Hey! I need some critical help here!" Unfortuantely, until our bodies break down and let us know there's a problem, most of us don't do anything to fix them until there IS a problem. Me included.
My daughter will soon be 13 years old, and I have been doctoring with alternative medicine for the past 5 years, trying to nurture my body and cure the damage caused from having her. I'd have her all over again, but it sure does s*ck to have to work so hard at being healthy again. However, I do have to say that at least I know the issues now so I can take steps to ensure that my body is healthy from now on.