Toxoplasmosis is an infection caused by parasite Toxoplasma gondii. Most common in pregnant woman, it poses a danger of being passed on to the unborn child. This can cause congenital defects and even death of the fetus. Mostly passed on through contaminated food and water, the infection is fairly common and tests for it are recommended at all stages of pregnancy. Two antibodies that the parasite triggers in the blood are IgM and IgG. Of these, IgM is specific only to the fetus. Therefore presence of these can give a strong insight into the fetus' health.