The noises and vocalizations involved in labor may unnerve the cat to the point of aggression. Neither of you need the added stress. Proceed with the introduction described above after all is calm. Not all cats love babies. Do not be surprised if Kitty goes into hiding after the baby arrives.
Some cats simply ignore the baby.
In both cases, allow the cat time to realize that everything's all right. No matter what your cat's reaction is, however, find time every day to spend with the cat alone. It may be as little as five minutes of quiet talk or a grooming session. Keep the baby's food and medicine in separate places from the cat's. Bottles and packaging can look remarkably similar.