Comparison of maternal and umbilical cord blood selenium levels in term and preterm infants

Selenium is an essential trace element and has a main role in cellular antioxidant defense system. In very preterm babies, low selenium is associated with an increased risk of complications such as chronic neonatal lung disease and retinopathy of prematurity. This study was designed to determine and compare maternal and umbilical cord blood selenium levels in term and preterm infants.

From February 2008 to April 2008, 30 term (gestational age>37 weeks) and 30 preterm infants (gestational age<34 weeks) and their mothers were enrolled. Selenium concentrations in umbilical cord and maternal venous blood were measured by atomic absorption spectrometry.

The mean selenium concentration in term infants was higher than in preterm infants (124.80+/-13.72 microg/L vs 100.30+/-11.72 microg/L, P=0.0001). The mean selenium concentration in mothers of term and preterm infants was not significantly different (117.03+/-17.15 microg/L vs 110.56+/-17.49 microg/L, P=0.15). Cord selenium concentrations were strongly correlated with gestational age and birth weight (r=0.66, p<0.0001 and r=0.59, p<0.0001, respectively) when the data of all infants were analyzed together. None of the 60 women had a serum selenium level below the laboratory lower limit of normal (70.0 microg/L). Maternal selenium levels were correlated with cord selenium levels in their infants (r=0.40, p<0.001) when data of all newborn infants and mothers were considered together.

Mothers have a relatively good selenium status and serum selenium is not a significant predictor of preterm delivery in Isfahan. The cord selenium concentration in term infants is significantly higher than in preterm infants, but the cord selenium concentrations in both groups are in a suggested normal range.