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.
Gestation Period for Dogs: How Long is a Dog Pregnant The pregnancy period of a bitch lasts for around sixty to sixty four days or approximately nine weeks. This time period may vary based on the dog and the size of her litter.