Neonatal anaemia secondary to blood loss

Abstract

The newborn has a limited capacity to tolerate acute haemorrhage. Prompt diagnosis and therapy are essential for survival. Blood loss can occur in the newborn due to occult haemorrhage, prior to birth or during delivery, obstetric accidents, maternal haemorrhage, or secondary to recurrent blood sampling. Special precautions must be taken when events known to cause fetal haemorrhage have occurred during pregnancy. These include a maternal history of transfusion reaction in the absence of a transfusion, third trimester bleeding with placenta praevia, placenta abruptio and vasa praevia, emergency caesarean sections, twin pregnancies and amniocentesis. The clinical manifestations of post-haemorrhagic anaemia at birth depend on the extent and duration of blood loss. When acute massive blood loss has occurred, the infant is extremely pale and requires immediate transfusions or volume expanders. Although the haemoglobin may be normal initially, it rapidly falls within six to eight hours after birth. Other causes of extreme pallor in the newborn include asphyxia and anaemia secondary to haemolysis. Infants who have developed acute post-haemorrhagic anaemia are hypovolaemic, are neither jaundiced nor cyanotic, and respond to therapy with volume expanders. The clinical picture with chronic blood loss is usually mild and responds to conservative therapy with iron alone. Internal haemorrhage should be suspected when a 24 to 72 hour newborn rapidly deteriorates and has evidence for hypovolaemic shock without signs of external blood loss. The blood withdrawn for laboratory evaluation in the high risk newborn must be carefully monitored so that it can be replaced before the newborn becomes compromised.