Plasma tocopherol levels and vitamin E/beta-lipoprotein relationships during pregnancy and in cord blood.

Plasma tocopherol, beta-lipoprotein concentrations, and tocopherol/beta-lipoprotein ratios were studied during 40 normal pregnancies. The levels in 36 cord blood samples from the newborn of these pregnancies and in 25 normal nonpregnant women were also determined. In agreement with earlier studies plasma tocopherol levels rose gradually and significantly during pregnancy, while the levels in cord blood were much lower. Beta-lipoprotein concentrations showed similar changes as for tocopherol, rendering the tocopherol/beta-lipoprotein ration unchanged during gestation. The ratios in cord blood and in nonpregnant women were similar to those of pregnant women. A significant positive correlation (r=0.84, p less than 0.001) was found between tocopherol and beta-lipoprotein concentrations. The results indicate that the increased plasma tocopherol levels during pregnancy and the low levels in cord blood result from differences in plasma transport capacity.