A few weeks before your cat's delivery, you should prepare a birthing box. Set up the box in a quiet, dark, comfortable spot and show it to her. When she begins to look for a place to have her kittens, bring her back to the nesting box you've prepared. Your cat may want you to be present while she gives birth, or she may want to be left alone; while it is safe to pick up newborn kittens, keep your presence minimal after their birth or your cat may relocate her nest.
Choose a lidded box made of cardboard or plastic with sides high enough to keep the kittens inside. Laundry baskets or other containers with holes should be avoided, as they could endanger the newborn kittens. The box should allow plenty of room for the mother cat to get comfortable, without having lots of extra space that could cause the kittens to wander off.
Cut newspaper into strips and place plenty of it inside the box. The paper will absorb the delivery fluids and can be thrown away shortly after the birth.
Slice additional newspaper or rags into strips and keep it nearby. When you throw away the soiled bedding, replace with this supply. Avoid using material that isn't smooth and might catch on the kittens' claws or limbs.
Cut air holes in the sides of the box, high enough to prevent the kittens from escaping through them. Add a larger hole in the top of the box so the mother can enter and exit as needed.
Bring the cat's litter box, food and water dishes into the room nearby, but don't place them inside the nesting box. The mother cat will get a much-needed break when she leaves to eat or use the bathroom.
Old bedsheets or T-shirts make good bedding material. A flashlight nearby will allow you to check on the kittens without disturbing them by turning on the lights.
Do not let your cat outdoors if her due date is approaching, or she may choose to give birth outdoors.