I'm yet to have a child, so I can't comment on experiencing changes in my hair as a result of pregnancy and subsequent birth.

I have long hair and my hair goes through cycles of loosing lots and I mean clumps in the shower, when brushing etc... I'm lucky I have lots of hair and it's thick.

My hair dresser has said it is normal, so I'm not fussed about it.

Tho in saying that, I do notice when I'm stressed my hair loss increases.

Not much help in recommendations of products or how to stop it, just you're not alone in experiencing it.