This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Antenatal Care & Assessment of Fetal Well Being, Subject name: Gynaecology & Obstetrics
[{'content': 'Folic acid required in first trimester of pregnancy in a woman with a history of NTD is: \nSelect and explain. \nA. 100 microgram, B. 400 microgram, C. 4 mg, D. 5 mg', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C. 4mga. More than half of NTDs could be prevented with daily intake of 400IgM of folic acid throughout the periconceptional period.b. A woman with a prior pregnancy complicated by a neural tube defect can reduce the 23% recurrence risk by more than 70% if she takes 4mg (4000ug) of folic acid for the month before conception and for the first trimester of pregnancy.', 'role': 'assistant'}]