Mother cats may leave their kittens alone. This happens to new mothers and cat mothers who have given birth to too many kittens, because the mother cat is inexperienced and does not know how to take care of kittens; there are too many kittens. The mother cat couldn't take care of her, so she wanted to run away. Furthermore, when there are other smells on the kittens, the mother cat cannot smell the familiar smell and will ignore the kittens.