Bleeding Disorders in Neonates

The newborn infant is particularly susceptible to bleeding complications for a variety of reasons: physiologic deficiencies of coagulation factors (both quantitative and qualitative), influences of maternal disease or drugs, immaturity of blood vessels, vulnerability to birth trauma, and other conditions associated with bleeding, such as sepsis and asphyxia. 1-5 Physicians caring for newborn infants frequently must manage sick neonates who have either obvious or occult bleeding, the latter often masquerading as unexplained anemia or hypotension. 1-4 It is crucial to identify the underlying disease(s) in such cases because these infants require vigorous support with blood products as well as aggressive therapy for the underlying disorders. Clinicians often care for well neonates who have abnormalities in coagulation without obvious bleeding; such abnormalities usually represent primary coagulation defects that are either hereditary or immune-mediated. 1-5 In these cases, therapy is designed to correct the specific coagulation defect. Thrombotic complications, which may be either congenital (in the form of homozygous protein-C deficiency or antithrombin III deficiency) or acquired (via catheters, infection, or renal-vein thrombosis), also may present with bleeding in the neonate. Their diagnosis and management is discussed elsewhere. 1,3-5 Physiology of Neonatal Coagulation and Hemostasis The initial defense mechanism against bleeding is the vascular endothelium, which is developed inadequately in the neonate.