Whelping is the process of a dog giving birth. Normal whelping occurs in three stages: preparation (the cervix dilates over 12–24 hours), active delivery (puppies are delivered, usually 20–60 minutes apart), and expulsion of placentas. Whelping should always be supervised, and owners should know the warning signs of dystocia (difficult birth) that require emergency veterinary assistance.
Stage one labour begins 12–24 hours before the first puppy arrives: the dog becomes restless, pants, may refuse food, seeks isolation or nesting spots, and her body temperature drops from normal (101–102°F) to below 99°F — an 8–12 hour warning that active labour is imminent. Temperature monitoring twice daily from day 58 of pregnancy helps predict this timing. Green or black vaginal discharge before any puppy is born is normal; bright red blood in large quantities is not.
Puppies are delivered in individual amniotic sacs that the mother normally breaks and removes, licking the puppy vigorously to stimulate breathing. Each puppy should be followed by a placenta — count them to ensure none is retained, as retained placentas cause serious infection. The interval between puppies varies from 20 minutes to 2 hours. Longer intervals are not automatically alarming if the mother is not actively straining, but active straining for more than 30–60 minutes without producing a puppy is a veterinary emergency (dystocia).
Signs requiring emergency veterinary attention during whelping: active strong straining for more than 30 minutes without producing a puppy; more than 4 hours between puppies if more are known to be present; bright red hemorrhage; green or black discharge before the first puppy arrives; a puppy visible or palpable in the birth canal but stuck; or a mother that collapses or becomes unresponsive. Brachycephalic breeds (French Bulldogs, English Bulldogs, Pugs) are at very high risk of dystocia and most require planned caesarean sections.