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.
Pregnancy in the dog lasts approximately 63 days. Just because a bitch was bred, however, does not necessarily mean she has become pregnant. Determining if a bitch is pregnant. For the first three weeks or so of pregnancy, you may not notice any changes in the bitch. Some females will become more demanding for attention, their nipples may enlarge slightly, and some may become hungrier. These are not a guarantee of a pregnancy, but are good signs.