This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Congenital Infections, Subject name: Pediatrics
Risk of transplacental transmission of toxoplasma gondii is maximum when mother is infected: 
Select and explain. 
A. Prior to conception, B. During first trimester, C. During second trimester, D. During third trimester
D: During third trimester
Answer: D: During third trimester 
Explanation: Risk of fetal infection in acute maternal toxoplasmosis increases with each trimester of pregnancy being 15%, 25% and 60% in 1st, 2nd and 3rd trimesters respectively But severity of fetal infection is much greater in early pregnancy.