<prompt> Which vitamin deficiency is most commonly seen in a pregnant mother who is on phenytoin therapy for epilepsy?Vitamin B6Vitamin B12Vitamin AFolic acid  <response>: Phenytoin inhibits the enzyme intestinal conjugase, an impoant enzyme in folic A. Metabolism. Folate is present in food in a polyglutamate form. This is conveed into monoglutamates by intestinal conjugase to be absorbed in the jejunum. Phenytoin acts by inhibiting this enzyme thereby causing folate deficiency and thus megaloblastic anemia. 