Vitamin A and vitamin E in umbilical artery and vein.

Vitamin A and vitamin E concentrations were measured in 27 umbilical arterial and venous plasma samples obtained from 24 singleton pregnancies and one triplet pregnancy. The levels of both vitamins were similar in arterial and venous plasma (mean +/- S.D. vitamin A 209 +/- 41 micrograms/l and 220 +/- 51 micrograms/l; vitamin E: 2.31 +/- 0.74 mg/l and 2.31 +/- 0.76 mg/l, respectively), but individual differences were observed in some cases. A significant relationship (p less than 0.001) existed between the arterial and venous levels of both vitamins. However, when arterial vitamin A levels were plotted against venous levels, the slope of the regression line (0.61) was significantly (p less than 0.01) different from unity, which suggests that the placental transfer or fetal storage has an effect on the arterial-venous ration of this vitamin. The vitamin A values from the triplet pregnancy were quite low, but comparable with each other.