Cats and pregnant women should not come into contact because cats can be infected with Toxoplasma gondii, and infected cats can re-infect pregnant women through their feces. If a pregnant woman is infected with Toxoplasma gondii for the first time, it may lead to fetal malformation or miscarriage or stillbirth. Cats acquire Toxoplasma gondii infection mainly through infected cat feces and by feeding on mice and birds. Only cats infected with Toxoplasma gondii for the first time will transmit eggs during the first two weeks of infection, and infected cat feces contain Toxoplasma gondii cysts. The fecal excretion of cysts in cats does not take long after infection, being 10-20 days. The cysts need to develop outside for 1-2 days, or longer, before they become infectious. If a cat infected with Toxoplasma gondii comes into contact with a pregnant woman during the infectious period, the pregnant woman will be susceptible to Toxoplasma gondii infection.