A dog that sheds black thick fluid before giving birth means that the placenta is about to give birth. Normal dogs will shed dark green fluid before giving birth and about two weeks after giving birth, but the color is darker, so it looks like Like black. During this period, you must pay attention to your dog's hygiene to avoid breeding bacteria and contracting skin diseases, but do not bathe your dog first to avoid catching a cold. You also need to supplement nutrients and calcium for your dog, otherwise your dog will be weak and unable to produce milk easily.