Haemostatic profile of full-term, healthy, small for gestational age neonates

Small for Gestational Age (SGA) neonates often appear with haemostatic alterations, principally due to hepatic dysfunction that results from chronic intrauterine hypoxia. Polycythaemia and thrombocytopenia are common findings in this neonatal population.

We performed a comparison of coagulation, natural inhibitors and fibrinolysis between SGA and Appropriate for Gestational Age (AGA) infants born full term [gestational age (G.A.) >37 weeks]. Study population consisted of 188 healthy newborns, 90 of whom were SGA (62 females and 28 males), while the rest were the control group (44 females and 54 males). Blood samples were obtained within 30 minutes following birth and before the administration of vitamin K. Investigation included: PT, INR, APTT, fibrinogen, coagulation factors II, V, VII, VIII, IX, X, XI, XII, vWillebrand factor, protein C and free protein S, antithrombin (AT), APCR, tPA and PAI-1. The independent t-test was used to compare the differences between the values of haemostatic parameters.

Statistical analysis revealed a significant prolongation in PT, INR, elevated levels of tPA (p<0.015, 0.01 and 0.002 respectively) and a decrease in the values of XII and free protein S (p<0.045 and 0.007 respectively) in SGA full term neonates. The two groups had similar demographic characteristics (except birth weight), without significant differences in the values of other haemostatic parameters.

Despite of statistically significant differences in PT, INR, values of tPA, XII and free protein S, levels of haemostatic factors range within laboratory references for healthy full term newborns. These findings were not accompanied with clinical manifestations of altered haemostasis.