The normal pulmonary vascular transition at birth

To fully understand the pathophysiology of the infant with congenital diaphragmatic hernia, it is important first to understand the multiple processes involved in the normal pulmonary vascular transition at birth. This article reviews the embryogenesis of the pulmonary vasculature, including angiogenesis and vasculogenesis, and the possible role that growth factors, growth inhibitors, and mechanical forces have in the normal development of the pulmonary vasculature. Also described are the multiple vasoactive substances that modulate pulmonary vascular tone in the fetus, and stimuli and agents that initiate and mediate the transition at birth.