THE ROLES AND VITAL IMPORTANCE OF PLACENTAL BLOOD TO THE NEWBORN-INFANT

At 30 weeks' gestation, half of the approximately 110 ml/kg total bloo d volume (BV) of the feto-placental circulation is in the fetus, risin g, by term, to about 90 ml/kg. In preterm infants at birth, subnormal blood volume is the rule, because of immediate cord clamping. Blood vo lume, typically 50-60 ml/kg during critical care, limits systemic oxyg en (O-2) transport and, because of shunting, causes hepato-splanchnic ischaemia and impaired lung function. Haemoconcentration results from plasma extravasation because of vascular endothelial damage. This elev ates the haematocrit, masking the red cell lack. By allowing placental transfusion at birth, delaying cord clamping by 30-60 seconds, initia l oligovolaemia is obviated, and post-natal lung adaptation greatly fa cilitated. The complications and costs of care san thereby be much red uced. Losses of haemopoietic stem cells are reduced, vital for haemato logic and immunologic constitution and for response to haemopoietic gr owth factors. Further work is urgently needed to determine how to opti mize this vital opportunity in preventive medicine in perinatology, wi th the objective of preventing complications, and reducing costs of al l kinds, in management of the infant born preterm.