Objective To determine oxygen free radical activity in breech presentation at birth and relate it to umbilical cord blood acid-base status. Design A series of 63 singleton deliveries (28 cephalic deliveries as controls), 23 breech deliveries with normoacidemia, and 12 breech deliveries with mild acidaemia) had determination of malondialdehyde and acid-base parameters. Setting The delivery suite in the Department of Obstetrics and Gynaecology at the Suleyman Demirel University, Isparta, Turkey. Participants Sixty-three singleton infants born at term with spontaneous or induced labour and initially normal fetal heart rate tracing. Methods After delivery, umbilical cord arterial and venous blood samples were collected for the determination of malondialdehyde concentrations. Oxygen saturation, pO(2), pCO(2), pH, and base excess were also measured. Main outcome measures Umbilical cord arterial and venous blood gases and malondialdehyde levels. Results There was a significant correlation between umbilical arterial and venous levels of malondialdehyde and all acid-base parameters (P < 0.001). There were negative correlations between malondialdehyde levels and pH, pO(2) and bicarbonate, while there was a positive correlation between malondialdehyde concentrations and pCO(2). A positive correlation between malondialdehyde levels and base excess was present in the control group and total breech group (n = 35). The malondialdehyde levels in the total breech group, nonacidaemic breech group (n = 23) and the mildly acidaemic breech group (n = 12) were significantly higher than those in the control group (P < 0.0001). However, acid-base parameters in the nonacidaemic breech group were not statistically different from those in the control group. Conclusion Lipid peroxidation products (malondialdehyde) existed to some extent in the umbilical cords of newborns with normal acid-base parameters in breech delivery. Our data support the contention that lipid peroxide may be a more sensitive measure for metabolic dysfunctions due to fetal hypoxia than acid-base balance.
