Dogs can have a small amount of discharge normally up to 6-7 weeks after whelping. It should not be a steady flow, nor have a foul smell. If your dog is acting off--not eating, not drinking, or lethargic then she should be examined by a veterinarian.
Reddish discharge after the devilry of puppies in dogs does not last long and there is no reddish discharge after the passing of placentas. Only dark green or dark color discharge for three weeks after whelping is normal. Presence of bloody or watery discharge after the delivery of puppies occurs when placental sites do not recedes. This discharge is abnormal.
Give or take 2 weeks.