In medicine, etiology refers to the many factors coming together to cause an illness. It is normally the focus of epidemiological studies. The etiology of scurvy is a good example. With scurvy, sailors going to sea often lacked fresh vegetables.
So, how long are dogs pregnant? The answer varies depending on several factors, but the average length of gestation, aka pregnancy, lasts between 58 to 67 days, with 63 days being the average delivery date.
Most dogs are pregnant for between 58 days and 64 days. The due date varies slightly depending on the breed and size of dog as well as the size of the litter she is carrying, but vast majority of dogs will give birth on the 63rd day. If you know the date your female dog mated, you can count 63 days from that date