Ascorbic acid concentrations in umbilical cord veins and arteries of preterm and term newborns.

Ascorbic acid (AA) is a powerful antioxidant required for the defense against oxidative stress. At present it is not known whether AA may play a role in the developmental process of the fetus. We therefore determined the relationship of AA levels between the umbilical cord vein (UCV) and umbilical cord artery (UCA) of preterm ( < 37 weeks of gestation) and term ( > or = 37 weeks of gestation) infants and compared those levels to matched maternal venous AA levels. We also assessed the association between UCV plasma AA levels with birth weight and gestational age by measuring AA in 88 UCV plasma samples and 58 UCA plasma samples obtained from newborn infants ranging in gestational age from 24 to 42 weeks and birth weight from 675 to 5,020 g, by high pressure liquid chromatography. Maternal venous samples were collected at the time of delivery. The mean UCV plasma AA levels (mg/dl) were significantly lower in the preterm group than in the term group (0.43 +/- 0.59 and 1.16 +/- 0.97, respectively; p < 0.002); however, the mean UCA plasma AA levels did not differ between the groups. In contrast, mean maternal venous plasma AA levels of the preterm group (1.33 +/- 0.62) were significantly higher than those of the mothers in the term group (0.72 +/- 0.69; p < 0.01). A direct correlation was found between UCV levels and birth weight (r = 0.23, p < 0.05), and UCV levels and gestational age (r = 0.23, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)