New evaluation of fetal oxidative stress: measurement of the umbilical cord blood dimethyl sulfate-induced ascorbyl-free radical by an electron spin resonance method.
The aim is to evaluate intrapartum fetal oxidative stress in real-time by umbilical cord blood dimethyl sulfate (DMSO)-induced ascorbyl-free radical (AFR) measured by an electron spin resonance (ESR) method. Seventy-five mothers delivering at gestational age after 37 weeks were recruited. They were divided into three groups: spontaneous vaginal birth (n = 27), elective cesarean section (CS) (n = 34), and emergency CS due to non-reassuring fetal status (n = 14). Umbilical artery (UA) and venous (UV) cord blood gas analysis was performed. Serum levels of DMSO-induced AFR (AFR/DMSO) that reflect vitamin C concentrations were measured by ESR spectroscopy. Blood gas analysis showed no significant differences among the groups. UA-AFR/DMSO level of elective CS group was significantly lower compared with spontaneous delivery group (0.32 ± 0.12 versus 0.46 ± 0.14, p < 0.005). Emergency CS group showed significantly lower levels of UA-AFR/DMSO compared with elective CS group (0.25 ± 0.11 versus 0.32 ± 0.12, p < 0.005). UV-AFR/DMSO levels had no significant difference among the groups. It is suggested that fetal cord blood AFR/DMSO is a sensitive marker to assess fetal oxidative stress during delivery.