Unfortunately sometimes kittens, like puppies, can be born with one or more defects.  Sometimes these defects can be traced back to genetic factors; however, there are defects that may be caused by humans and the environment that could potentially be avoided.  It stands to reason that pregnant cats should not be exposed to harmful toxins.  For example, exposure to household cleaners containing harmful chemicals or exposure to environmental toxins outside of the confines of the home could result in deformities.  Hyperthermia, while a cat is pregnant, can result in kitten birth defects.  Keeping pregnant cats away from toxins or avoiding hyperthermia is particularly critical in the early stages of pregnancy.

 Likewise, avoiding certain vaccinations or certain medications while caring for a pregnant cat can lessen the probability that a cat will give birth to kittens with defects.  For example, many deworming products and flea products should be avoided unless your veterinarian states that the product is safe for pregnant cats.  Tapeworm medications can be particularly toxic to pregnant cats as well.  Avoid administering live virus vaccines to a pregnant cat.  For example, if a pregnant cat is given a live vaccine against panleucopenia, a disease that can be fatal to cats, cells in the developing erebellum of a kitten could be destroyed.  Likewise, administering a live vaccine of griseolfulvin, which is used to treat ringworm, can cause congenital defects such as cleft palates.

 In addition to the avoidance of harmful toxins or medications, making sure that a pregnant cat has proper nutrition is also extremely important.  Having low levels of nutrients such as zinc, copper or manganese can result in limb deformities.  Maintaining a proper weight for a pregnant cat can also help to reduce the possibility that kittens will be born with health problems.

  As previously mentioned, some kittens are born with defects resulting from genetic factors.  As responsible cat owners, we can help to reduce the influence these genetic factors by being educated on proper breeding practices.  Inbreeding, or breeding closely related cats, can cause birth defects.  There are some breed-specific abnormalities in cats that can also be reduced by selective breeding.  If there appears to be a genetic cause for a particular defect, then the parents and the offspring should perhaps be neutered in order to prevent further spread of the defect.

As is the case with all pets, reducing the incidence of kitten birth defects can be done through educating oneself regarding the toxins, medicines, and poor breeding practices that need to be avoided.