My friend swore by Mama's Choice Hair Loss Treatment Shampoo and Conditioner during her pregnancy, they're specifically made to be pregnancy-safe and breastfeeding-safe, and she said they really worked for her hair fall which was quite bad after birth. Since they're formulated without the harsh stuff, many mums use them from pregnancy onwards too, so worth a look if you want something you can trust.
Try the mamaschoice pregnancy shampoo and conditioner! It really works. Can buy them at motherswork