The major concern and biggest risk of toxoplasma is if you became infected for the very first time during your pregnany. About 40-50% of women test positive for toxoplasmosis before pregnancy and are unlikely to infect the fetus. If a woman has no history of the infection and doesn't carry the antibody at the beginning of her pregnancy, she and her fetus are at higher risk if she does come down with a primary toxoplasmosis infection while pregnant. A simple test for a protein called IgG will tell you if you have had it before or not.

During the first trimester, only about 10% of fetuses become infected if the mother is infected, but the illness increases the risk of fetal complications, including severe congenital malformations and even death. After the first trimester, there's about a 60% chance that the fetus will become infected if the mother has a primary T. gondii infection, though at this stage, the majority of fetuses will have few or no symptoms. Presently, there are no recommendations in the U.S. for routinely testing pregnant women for toxoplasma. A positive result during pregnancy can be confusing because it's difficult to pinpoint the exact time of infection. The best time to get tested is before you get pregnant. If you test negative before or early in pregnancy, take precautions to prevent a toxoplasma infection: Avoid exposure to cat feces, and don't eat undercooked or raw meat. And get tested again later in pregnancy to make sure you haven't become infected.

More Toxoplasma FAQs at Palo Alto Medical Foundation