Many couples have a cat for many years before starting a family, but reject the cat once a baby is due. A timid cat which is over-dependent on you, but hides from other people may become jealous and spray to cover up the scent of the baby. It needs to become less dependent on you well before the birth. A devoted cat that joins in human activities will have hurt feelings, but is likely to join in with caring for baby if you let him. An independent cat who treats you like a hotel will probably ignore the baby if hotel services remain unchanged.
Many cats become protective of what they view as a 'people-kitten'.
There was one confirmed case where the baby inhaled the cat's fur and its breathing was obstructed. Get information from your doctor and your vet about cat-borne organisms that can harm unborn babies and take appropriate precautions e.g. don't handle soiled cat litter and scrub garden vegetables before eating them. Ensure Puss is healthy and vaccinated. Establish the cat's new routine gradually. Let him sniff the crib, pram etc but teach him not to get inside them.