This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
[{'content': 'All of the following statements are true about congenital rubella except: \nSelect and explain. \nA. It is diagnosed when the infant has IgM antibodies at birth, B. It is diagnosed when IgG antibodies persist for more than 6 months, C. Most common congenital defects are deafness, cardiac malformation and cataract, D. Infection after 16 weeks of gestation results in major congenital defects', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. is \'d\' i.e., Infection after 16 weeks of gestation results in major congenital defects(Ref: Harrison, 18th/e, p. 1606; 19th/e, p. 1300)* The most important factor in the pathogenicity of Rubella virus for the fetus is gestational age at the time of infection.* "In general, the earlier in pregnancy infection occurs, the greater the damage to the fetus. Maximum damage to the fetus occurs when infection acquired in the first trimester of pregnancy."* Risk of damage to fetus by maternal rubella during pregnancy.* Birth defects are uncommon if maternal infection occurs after the 20th week of gestation.', 'role': 'assistant'}]