Can a pet cat cause toxoplasmosis in pregnant women?
Cats aren't likely to transmit the infection, but it is possible.
Once upon a time, doctors used to routinely advise pregnant women to avoid cats -- leading many women to give up their cats or to worry over even the tiniest cat scratch during pregnancy. But do cats really increase the risk of miscarriage?
It is true that cats can be carriers of the microorganism known as (also known as T. gondii), the cause of the disease toxoplasmosis.
It is also true that toxoplasmosis is one of several infections that can cause miscarriage, a pregnancy that ends on its own within the first 20 weeks of gestation (usually in the first trimester).
However, this does not mean that having a cat automatically puts you at higher risk of miscarriage. In fact, the riskiness of owning a cat while pregnant is sometimes rather exaggerated. For instance, one 2000 study actually found that the largest risk of toxoplasmosis in pregnancy was from eating undercooked meat, and that cat ownership was rarely a problem.
Reasons Why Cats Rarely Transmit Toxoplasmosis to Pregnant Women
First of all, cats are not usually chronic carriers of T. gondii. They tend to acquire it, and then they develop antibodies and no longer transmit T. gondii. So, in order for a house cat to pass toxoplasmosis to its owner, a cat must have had recent exposure to T. gondii and
has not yet developed circulating antibodies against the infection.
Secondly, outdoor cats tend to be exposed to T. gondii far more frequently than indoor cats; toxoplasmosis in indoor cats is rare. T. gondii is most commonly found in rodents and raw meat, so a cat who lives only indoors is unlikely to be exposed to it unless the owner regularly feeds the cat raw meat.
Finally, the means of transmission from cat to owner would most likely be through the owner's exposure to cat feces. The pregnant woman would have to change the cat litter box, touch the feces, and then somehow put the T. gondii into her mouth -- and it's safe to say that most people would probably wash their hands in between changing cat litter and touching their mouths!
Sensible Precautions for Cat Owners
All in all, the risk of a pregnant woman acquiring toxoplasmosis from a house cat is rather low. That being said, the Centers for Disease Control and Prevention suggests following these precautions to almost entirely eliminate your risk of cat-borne toxoplasmosis:
Get someone else to change the cat litter if you can. And if you can't, wear gloves while changing it and wash your hands carefully with soap and hot water afterward.
Change the cat litter daily. The microorganism is infectious between one and five days after the cat defecates.
Do not feed your cat raw meat. Keep your cat indoors.
Be careful around stray cats and kittens, and avoid getting a new cat while pregnant.