According to Cat World, a cat's pregnancy typically lasts 63 to 65 days. However, the length of a pregnancy varies between cat breeds, and it is possible (although uncommon) for a cat's pregnancy to be as short as 60 days or as long as 70 days.
Cat World says that it is impossible to tell if a cat is pregnant by doing a urine or blood test. However, by the third week of pregnancy, the cat's nipples become enlarged and extremely pink. This is referred to as "pinking up" and is a clear sign that a cat is pregnant. By the third to fourth week, a veterinarian is able to feel the babies in the cat's abdomen.