The immature skin.

The skin of the extremely preterm infant is structurally and functionally immature at birth, although there is rapid postnatal maturation. The consequences of this immaturity are a high transepidermal water loss (leading to hypothermia and difficulty in fluid balance) accidental percutaneous absorption and toxicity, and skin trauma (leading to infection). Neonatologists must be aware of these and take measures to limit them.