Normally the oppostie is true, during the cyclic shedding stops and the coats get lusher and fuller (as in humans). After weaning is when the bitch will usally have a horrific moult almost down to bare skin.
Agree with Brainless, my girl could make a nice rug after weaning, but don't worry all bitches are different the majority will have a big shed afterwards but as we know there are always exceptions in everything, just make sure that she is on a good complete food and is eating and drinking well. :-)