I have also heard that they can lose their coats after they have puppies, mine didn't, but she did have discharge/bleeding even after 9 weeks. We had to get her spayed... at first they thought maybe she retained a piece of placenta, (I didn't agree since it was clean blood, not green or smelly) After the surgery they had told me that she was in a constant "heat" since birth, even though her bottom wasn't swollen... her hormones were screwed up also because of this.
She is now, after a few days after the surgery, comming back to my baby girl I once had
What I can't understand, is even though her milk is almost gone, she will let the one pup we have left her try and nurse, right next to her incision
she loves her pups... we had to put her in a onsie to get her to stop nursing at 7-8 weeks so she could have surgery.
As the time went on (after the first couple of weeks of after birth bleeding) her bleeding was getting worse, so I know we did the right thing (spaying her).
Good luck with the pups
and mom.