SC Differences Between Premature and Term Neonates
Term neonates have a well-developed SC containing 10–20 layers.5,21 In premature neonates, depending on the neonate’s gestation age, the SC may only have 2–3 layers.5,21 The immaturity of the SC may result in increased moisture and heat loss leading to electrolyte imbalance, reduced thermoregulation, and increased infection risk.3-6,21 Cohesiveness of the epidermis to the dermis differs in premature and term infants. Fibrils providing the cohesion between the epidermis and dermis are fewer and more widely spaced in preterm neonates.3-6,21 This decreased cohesion increases the risk of skin injury, and thus the use of adhesives on the skin of neonates, especially premature babies, should be limited. If the adhesive used forms a stronger bond with the epidermis than the epidermis to the dermis, skin breakdown is likely.21-23
Differences in the skin surface pH also exist between premature and term newborns.4-8,21 A slightly acidic skin surface plays an essential role in the maturation and maintenance of the SC, also inhibiting the growth of pathogenic microorganisms.21 The vernix caseosa layer on the skin helps maintain skin hydration, thermoregulation, and skin acidification.8 Premature infants of varying gestational ages and term infants are born with a more alkaline skin surface (pH >6.0).21-23 For term infants, this usually falls to less than pH 5.0 within the first three days of life, providing a functional SC barrier.21-23 Due to an immature skin structure and the reduced or negligible amount of vernix caseosa, the premature infant, has an alkaline skin surface for a more extended period.5,8 The skin pH of a premature infant may take one week to decrease to pH 5.5 and up to a month to reach pH 5.1 and is therefore even more susceptible to xerosis, skin irritation, and infection at this time.4,21-24
An unbalanced skin microbiome may also play a role in the newborn period.24 The skin microbiome in infants born vaginally has shown to be different from those delivered by Caesarean section. The clinical relevance of this finding needs further research regarding the potential of resultant dermatoses, which may benefit from skincare containing SC lipids such as ceramides.14,16,24,25
