A cat can be judged when pregnant by its weight gain. Usually cats tend to feel sick in the mornings when pregnant. They may also feel more hungry at the time of pregnancy. A behavioral change will also be noticed, a pregnant cat is often quiet. they also start showing more affection to the owner.
A cats gestation period only lasts about 60 to 65 days, to find out how far along they are you can check their nipples. The more red and swollen they are the further along the cat is to giving birth, by three weeks they are much more distinguishable than they had been.
there is no way, apart from an ultrasound which will be expensive, to really tell until a couple of days before she gives birth when she will start producing milk and nesting. Gestation in a cat is 9 weeks.
