Your cat is very likely hiding her kittens from you as a natural maternal instinct. Cats want to keep their kittens in a safe, clean, quiet space in order to help their chances of survival. Even in a safe home environment, this instinct can drive a mother cat to seek secluded spots she thinks are secure for her offspring.
Pregnant cats – technically known as Queens! – will often start looking for a suitable place to have their nest a couple of weeks before the kittens arrive. You can help by providing some warm, comfortable options in quiet areas of your home for your cat to choose from. For instance, you could try a laundry basket, under a bed, or behind some furniture. Then, once the kittens have arrived, keep their chosen spot as quiet and safe as possible.
Don’t forget, as exciting as it is to see your cat’s new kittens, it’s important to give them their privacy. Keep children, visitors, and other pets away, and keep an eye on the kittens from a distance. After two weeks or so, you may start to see them emerge!