This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'Vitamin deficient is most commonly seen in a pregnant mother who is on phenytoin therapy for epilepsy? \nSelect and explain. \nA. Vitamin B6, B. Vitamin B12, C. Vitamin A, D. Folic acid', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Phenytoin interferes with metabolism of folate and patients taking phenytoin may become deficient in folic acid. Phenytoin decreases absorption of folic acid and increases its excretion. Ref: Advanced Therapy in Epilepsy By Wheless, James W. Wheless, James Willmore, Roger A. Brumback, 2009, Page 259.', 'role': 'assistant'}]