lung changes at birth

Last reviewed 01/2018

The follows changes occur at birth:

  • lung liquid is reabsorbed - chest compression squeezes out a third of the fluid, adrenalin promotes reabsorption of the rest.
  • surfactant is released, triggered by adrenalin and steroids. Synthesis is also begun.
  • a fall in the capillary pressure of the lungs occurs with the expansion of the alveoli, and the vasodilatory effect of oxygen. Other circulatory changes take place - physiological closure of the ductus arteriosus and foramen ovale, such that whole of the cardiac output flows via lungs
  • respiratory movements of the chest commence