Vitamin B6 nutriture during pregnancy and lactation. II. The effect of long-term use of oral contraceptives.

Vitamin B6 nutriture was assessed during pregnancy and lactation to determine whether previous use of oral contraceptive agents (OCA) resulted in reduced reserves of the vitamin. Vitamin B6 levels were measured in maternal serum and urine at 5 and 7 months gestation and at delivery, in cord serum and in milk at 3 and 14 days postpartum. Long-term use of OCA (greater than 30 months) resulted in low levels of vitamin B6 in maternal serum at 5 months gestation and at delivery and in milk compared with values for short-term (1 to 30 months) and nonusers of OCA. Levels of vitamin B6 were also lower in the cord serum of long-term users of OCA as compared to nonusers.