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.
The dog's pregnancy will last between 58-68 days, with 63 days being the norm. One of the first ways that you can tell that your female is pregnant is to look at her abdomen. The stomach area will swell and depending on the size of the litter, will be quite larger than usual as the pregnancy progresses.