Low molecular weight plasma antioxidants and lipid peroxidation in maternal and cord blood

Objective: To determine the concentrations of the low molecular weight anti oxidants urate, bilirubin, albumin and sulphydryl groups and to measure lip id peroxidation levels in pair-matched maternal and cord blood plasma. Design: Venous blood plasma concentrations of urate, bilirubin, albumin and sulphydryls were determined in healthy pregnant women and in pair matched umbilical cords. The ability of maternal and cord plasma to withstand Cu2+- induced lipid peroxidation was assessed by measuring the production of thio barbituric acid reactive substances (TBARS) over time in plasma incubated w ith Cu2+. Subjects: Forty healthy women, between 10 and 20 weeks gestation, were recr uited randomly from an antenatal clinic. Venous blood samples were obtained from the mothers at the recruitment stage and from the umbilical cords of their newborn after delivery. Results: Urate, bilirubin and sulphydryls were present in significantly hig her concentrations (P < 0.001) in cord plasma than in maternal plasma. Albu min levels were similar in mothers and cords. Significantly lower levels (P = 0.018) of TBARS were produced in cord plasma compared with maternal plas ma following incubation with Cu2+. There were significant correlations betw een albumin and sulphydryl concentrations in maternal plasma (r 0.43, P = 0 .007) and between urate concentrations in maternal and cord plasma (r 0.37, P = 0.026). Conclusion: Urate, bilirubin and sulphydryls are present in significantly h igher concentrations in cord blood than in maternal blood. The increased le vels of these antioxidants in cord plasma may contribute to the increased r esistance of cord plasma to Cu2+-induced lipid peroxidation. Sponsorship: University College Cork, Ireland. Descriptors: pregnancy; neonates; blood plasma; antioxidants; lipid peroxid ation.