Arrival of a baby results in dramatic lifestyle changes. As we try to emphasize at Worms & Germs, pets are a part of the household, and they can also be affected by the new arrival. While most pets handle the transition well, there can be some concerns. Foremost is aggressive behaviour towards the baby, which may occur due to inadvertent rough play, anxiety at household changes, territoriality or other causes. Even previously "perfect" pets can develop (and cause) problems as the social structure of the household changes. The potential problems can also change over time, as the baby starts to crawl, and starts to try to touch the pet or its toys or food bowls. Bites and scratches can occur, sometimes with tragic results.

General recommendations for introducing a baby to your pet are available, including "And Baby Makes Four" and "Preparing Your Pet For Baby’s Arrival" from the Calgary Humane Society. The Calgary Humane Society offers a program call New Baby, Old Pet, which is designed to help families make the introduction of babies to pets safe and happy. If you are expecting a new arrival in your family, you should consider contacting your veterinarian, local humane society or public health unit to see if a similar program is available in your area.