Effect of oral contraceptives on nutrients. III. Vitamins B6, B12, and folic acid.

The interactions of oral contraceptive agents (OCA's) with vitamins were studied in a large population of women. In the upper socioeconomic groups, higher incidences of abnormal clinical signs related to vitamin deficiencies were seen in OCA users than in the control subjects. Plasma pyridoxal phosphate and red cell and serum folate were lower in subjects using OCA's in the upper socioeconomic group as compared to levels in the control subjects. Reduction in erythrocyte glutamic oxalacetic transaminase (EGOT) activity and elevation in the EGOT-stimulation test were observed in subjects using OCA's in both upper and lower socioeconomic groups. These observations suggest a relatively deficient state with respect to vitamins B6 and folic acid in OCA users. No significant effect on serum vitamin B12 was observed as a result of OCA administration.