- 1). Check your cat's nipples. Three weeks after a cat becomes pregnant, her nipples start to swell up and turn a brighter shade of pink.
- 2). Pay attention to your cat's behavior. Along with an increased appetite, behavioral changes are common in pregnant cats. Sometimes a cat will become more affectionate, and other times she may become extremely irritable when touched.
- 3). Pay attention to the size of your cat's belly. A cat that is pregnant -- and not just fat -- will develop an enlarged stomach by week four, although the rest of her body stays relatively the same size. Belly size can be tough to recognize in larger, more plump cats.
- 4). Be on the lookout for "nesting" behavior, which begins late in the cat's pregnancy, around week seven. Your cat may gather blankets, clothes and other items to build a comfortable home for her kittens after they are born. Common places to look for the nest are in quiet areas, such as under a bed and in a closet.
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