Adenosine concentration in umbilical cord blood of newborn infants after vaginal delivery and cesarean section

Abstract

Umbilical blood was collected immediately at birth (<30 s) in full-term infants after vaginal deliveries (n = 33) and elective cesarean sections (n = 11). Blood gases, plasma adenosine, hypoxanthine, and catecholamine concentrations were determined. In vaginally born infants the median arterial adenosine concentration was found to be 0.46 μM (range 0.13-2.06) and the venous 0.48 μM (0.09-1.62). These levels were significantly higher (p < 0.01) than in infants delivered by elective cesarean section; 0.16 uM (0.04-0.42) in the artery and 0.17 μM (0.020.56) in the vein. Vaginally born infants showed about a 4fold higher level of umbilical arterial catecholamines than infants born by elective cesarean section. There was a strong inverse correlation between arterial hypoxanthine concentration and pH (r = -0.81, p < 0.01). It is suggested that increased adenosine release at vaginal delivery modulates the stress response elicited by the strong catecholamine surge and may furthermore exert protective effects in perinatal asphyxia. © 1989 International Pediatric Research Foundation, Inc.