Surfactant in lung alveoli stas appearing at gestational age

Surfactant does not normally begin to be secreted into the alveoli until between the sixth and seventh months of gestation, and in some cases, even later than that. Therefore, many premature babies have little or no surfactant in the alveoli when they are born, and their lungs have an extreme tendency to collapse, sometimes as great as six to eight times that in a normal adult person. This causes the condition called respiratory distress syndrome of the newborn. It is fatal if not treated with strong measures, especially properly applied continuous positive pressure breathing.Ref: Guyton and Hall Textbook of Medical Physiology, 12th edition, page no: 878