Cats have the ability to sense human pregnancy because they sense the pheromones produced by the body during pregnancy. Some women have noticed that when pregnant, their cats became more affectionate.
According to The Nest, cats pick up on human pheromones, changes in body language and a woman's growing belly. Some cats curl up next to the mother to feel the vibrations in her belly. According to BabyCenter, some cats sense a change because of changes in daily routine during pregnancy. However, cats are less likely than dogs to undergo behavioral changes, such as becoming more protective. Cats' responses to pregnancy are variable; while some cat owners have reported disinterested responses from their cats, others report that their cats become more loving and protective.