Scar formation after skin injury to the human foetus in utero or the premature neonate.

A macroscopically visible scar was present at birth in three infants with a history of injury during amniocentesis at 16-20 weeks' gestation. In several neonates born between 21 and 31 weeks' gestation, chemical injury to the skin caused by extravasation of calcium gluconate healed by formation of a large scar. In the infant born at 21 weeks, biopsy of the injured area showed infiltration by large numbers of neutrophils and macrophages. It appears that a very immature neonate can mount a prominent inflammatory reaction and that both a midtrimester foetus and a very immature neonate heal injuries to the skin by scar formation and not by scarless healing.