CD40LG and congenital toxoplasmosis: However, IgM testing reportedly fails to detect 50–75% of infected infants; therefore, 6–12 cases of congenital toxoplasmosis may have occurred between 2005 and 2008.29,30,39 The results of IgM testing in women of childbearing age with high-risk pregnancies (history of miscarriage) support this hypothesis, because 43 cases of toxoplasmosis acquired during pregnancy would be expected to result in 11–21 cases of congenital toxoplasmosis, assuming a 25–50% probability of transmission to the fetus in utero.