Whether you are thinking about breeding your cat or you are simply concerned that she might have accidentally become pregnant, you will find that there are a number of facts that you need to be aware of. While younger cats have a more difficult time getting pregnant than older cats, you will find that the cat pregnancy length, the time between mating and birth is actually quite standardized. For the most part, you will find that a cat's pregnancy length will last about 57 to 70 days. Many cats end up averaging around 64 days or so, giving them a pregnancy length of around nine weeks.
When you are trying to figure out if your cat is pregnant, there are a number of signs that you need to keep mind. The first sign that you are likely to notice is that your female cat will no longer come into heat. An unspayed female cat tends to come into heat every ten days or every two weeks. If she suddenly stops giving the signs of having gone into heat, there is a good chance that she might be pregnant. The first physical sign that you are likely to see is that her nipples will have a swollen, slightly tender look and they might turn pinker in color.
A cat that is pregnant will also tend to have an increased appetite as the resources in her body start being taken up by nourishing her kittens. In a human, you might refer to this as "eating for two," only in her case, it might be four, or five or more! Similarly, a pregnant female cat might also vomit, but if this happens more than a few times, a visit or a call to the veterinarian might be necessary. By the fifth week of her pregnancy, 35 days or so after contact with the tom, your cat's stomach will start to swell. From this point, she will tend to be growing almost continually until she gives birth.
Some people are alerted to a incipient pregnancy through the strange behavior of their cat. An increased amount of attention from a cat who was formerly aloof might be a dead giveaway, as is nesting, where your cat will start to seek out dark and quiet places to give birth. Conversely, a cat who gets closer to the date of giving birth might end up growing withdrawn or snappish. Certainly you will want to give her some space after she has given birth as she will be very protective of her kittens?
If your cat is pregnant, you might also be wondering how many kittens to expect. In general, litters will range between one and eight kittens, though four or five are perhaps the most common. If you are truly curious or you want to know for certain that your cat is pregnant, an ultrasound can be a good tool to use. A first litter for a cat will tend to be smaller.