If you think your cat might be pregnant, first check her nipples. These become more prominent and pinker by three weeks of gestation. By four to five weeks after conception, your vet will be able to feel golf-ball sized swellings in her abdomen. At this time the developing foetuses are usually quite easy to count. Shortly afterward, her belly becomes visibly enlarged.
The greatest risk to unborn kittens occurs during the first three weeks of development in the womb. Both drugs and infections might seriously impair healthy development. If, for example, the mother is exposed to feline infectious enteritis at this time the surviving kittens will be born with severe brain damage. Even exposure to certain live vaccines is dangerous.
Cats should be vaccinated before they are pregnant to increase the amount of passive protection they pass in the first milk to their kittens. Never vaccinate pregnant cats to increase the level of inherited protection. Never vaccinate other cats in the household of a pregnant cat. Live vaccine virus can be shed by vaccinated cats and affect the pregnant cat’s foetuses.
Pregnancy can be as short as 57 days or as long as 70 days, but a few days before birth the female becomes restless and searches out her chosen shelter. She rearranges her bedding material and spends increasing amounts of time in her chosen nest. This impregnates the region with her own scent, something that will eventually help her kittens orientate themselves toward home. As birth approaches, the mother loses her appetite and paces in the nest until contractions begin.