Highest rate of transmission of toxoplasmosis during pregnancy is seen in:

“The incidence and severity of congenital infection depend on fetal age at the time of maternal infection.The risks for fetal infection increases with duration of pregnancy from 6 % at 13 weeks to 72 % at 36 weeks. Conversely the severity of fetal infection is much greater in early pregnancy and fetuses are much more likely to develop clinical findings of infection." Williams Obs. 24/e, p 1255