Early signs that a cat is pregnant typically include physical and behavioral changes. Among the earliest physical signs are enlarged and pink nipples ("pinking up"), usually noticeable around 3 weeks into pregnancy, and gradual weight gain. The cat's abdomen begins to visibly enlarge around 4 to 5 weeks as the kittens grow. Other signs include changes in eating habits, such as increased appetite, as well as possible vomiting due to hormonal changes. Behaviorally, pregnant cats may become more affectionate or seek more attention, exhibit nesting behavior by seeking secluded places for birthing, and show signs of restlessness or lethargy as pregnancy progresses. These signs generally become noticeable from around 3 weeks into pregnancy and continue to develop over the following weeks.