Recently, oxidative stress was suggested to play a role in maternal and fetal complications of diabetic pregnancies. The aim of this study is to evaluate the global oxidant and antioxidant status in infants of diabetic mothers (IDM) via measurement of total antioxidant capacity (TAC) and total oxidant status (TOS) and to determine their association with the clinical and cardiac manifestations of gestational diabetes on infants. Forty five infants constituted the IDM group, 51 infants born to non diabetic mothers served as the control group. Umbilical cord blood was drawn from IDM and controls for TAC and TOS measurement. Echocardiographic measurements were performed in the first three days of life. Infants of diabetic mother had significantly higher TAC (p = 0.024), TOS (p = 0.03) and oxidative stress index (OSI, p = 0.04) levels compared to controls. Hemoglobin values were correlated to TOS (r = 0.310, p = 0.03) and OSI (r = 0.310, p = 0.03). Maternal HbA1c values were also correlated to TOS (r = 0.576, p = 0.001) and OSI (r = 0.606, p < 0.001). Systolic and diastolic interventicular septum measurements, and left ventricular mass were also correlated with TOS (r = 0.330, p = 0.02; r = 0.453, p = 0.002; r = 0.404, p = 0.006, respectively) and OSI (r = 0.330, p = 0.02; r = 0.300, p = 0.04, r = 0.300; p = 0.04, respectively). Oxidant-antioxidant balance is disturbed in favor of oxidants in IDM despite compensatory increase in TAC. The degree of oxidative stress is related to the severity of myocardial and hematological involvement in IDM in the first days of life and maternal glycemic control. (C) 2015 Elsevier Ireland Ltd. All rights reserved.