Influence of antenatal steroids and sex on maturation of the epidermal barrier in the preterm infant

Background-The epidermal barrier is well developed in term infants but defe ctive in the immature infant with important clinical consequences. The deve lopment of the barrier shares similarities with production of pulmonary sur factant. Studies in the rat have shown that barrier maturation is accelerat ed by antenatal steroids, both structurally and functionally. Females have a more mature barrier than males at the same gestational age. These factors have not been studied in the human. Aim-To examine the influence of antenatal steroids and sex on maturation of the epidermal barrier in the preterm infant. Subjects-A total of 137 infants born before 34 weeks gestation, 80 boys and 57 girls, were studied: 87 had been exposed to antenatal steroids, and 50 had not; 99 were studied prospectively, and 38 had been studied previously. Method-Barrier function was measured as transepidermal water loss from abdo minal skin by evaporimetry. Measurements were made within the first 48 hour s and corrected to a standard relative humidity of 50% (TEWL50). Results-The relation between TEWL50 and gestation was exponential with very high levels in the most immature infants. No influence of antenatal steroi ds or sex could be shown. When infants who were optimally exposed to antena tal steroids were considered alone, no effect could be shown. Conclusion-Epidermal maturation in the preterm infant does not appear to be influenced by antenatal steroids or sex, suggesting that the mechanism of maturation differs from that of the rat.