The normalization period of platelet aggregation in newborns

This study was performed to investigate the normalization period of the transient platelet dysfunction of newborns. A total of 43 healthy newborns of healthy mothers who had received no medication for at least 14 days prior to delivery were included in the study. Venous blood samples of 44 healthy volunteer adults were used as control. Platelet aggregation study was performed in whole blood by impedance aggregometry. Collagen or ADP was used as the aggregating agent. In the platelet aggregation studies using collagen, maximum aggregation values in the first three days of life were lower than those of adults (p < 0.001). These lower values were improved and reached adult values between the 5th and 9th day of life. Lower maximum aggregation values were observed in newborns in comparison with those of adults when ADP was used, but the difference was not significant except for 5 microM concentration of ADP. There was no significant difference between the aggregation time of the collagen and ADP groups (p > 0.05). In conclusion, the platelet responses to ADP and collagen were increased in newborns as the age progressed and reached normal levels between 5th and 9th day of life. If platelet dysfunction does exist after the 10th day of life, this finding may be due to either simple prolongation of the physiological phenomenon or platelet disorders.