I am having the same problem! I am gonna ask my doctor at my appointment Thursday.
Chunks of hair always have come out from me when brushing but it was due to hormonal changes. Unfortunately it still happens to me ever since my first, but Ive not gone bald. My hair hasnt thinned out either, but you can mention it to your Dr and see what they say too.
I had the same problem!! My doc checked my vitamin d and it was low. Stopped falling out so much for me at 20 weeks or so.
You should take magnesium & pregnacare. Then u will b fine!