78: Maternal and fetal oxidative stress and intrapartum term fever

Abstract

OBJECTIVE-The association between maternal chorioamnionitis and fetal oxidative stress has not been well established.STUDY DESIGN-A nested case control study was performed within a prospective cohort of term nulliparous women: 20 cases (intrapartum fever of >100.4°F) and 20 afebrile controls. Oxidative stress was assessed using ThioGlo-1 (TG-1; Calbiochem, San Diego, CA) fluorescent sulfhydryl detection. Median levels (± interquartile range) of protein-thiol sulfhydryls were compared.RESULTS-In early labor, maternal oxidative stress (lower protein sulfhydryls) was significantly higher in those women who subsequently had intrapartum fever develop (79.87 ± 22.88 vs 127.73 ± 43.79 counts/second per μg protein; P < .001). In contrast, cord serum sulfhydryls were not different between groups (75.77 ± 14.00 vs 75.04 ± 17.83 counts/second per μg protein; P = .99) CONCLUSION-Our data suggest that the term human fetus is protected from maternal oxidative stress associated with intrapartum fever. However, maternal oxidative status in early labor is associated with subsequent intrapartum fever. Optimal fetal neuroprotection will require a more precise knowledge of pathogenic mechanisms.Keywords fetal neuroprotection; fever; inflammation; intrapartum fever; oxidative stress Fetal exposure to chorioamnionitis (hyperthermia and inflammation) at term has long been accepted as a potent risk factor for neonatal encephalopathy and cerebral palsy. Chorioamnionitis accounts for between 11% and 22% of cases of cerebral palsy in near-term and term infants, and carries an odds ratio of 9.3 for otherwise unexplained cerebral palsy. 1,2 The current diagnosis of chorioamnionitis is largely based on maternal fever; fundal tenderness cannot be used after epidural analgesia and purulent vaginal discharge is a subjective finding. Maternal oral temperature is the best indicator of intrauterine temperature Presented orally at the 30th Annual Meeting, Society for Maternal-Fetal Medicine, Chicago, IL, Feb. 1-6, 2010. The racing flag logo above indicates that this article was rushed to press for the benefit of the scientific community.Reprints not available from the authors. HHS Public Access Author Manuscript Author ManuscriptAuthor Manuscript Author Manuscript but underestimates it by an average of 0.8°C. 3 In turn, fetal core temperature is approximately 0.75°C higher than fetal skin/intrauterine temperature. 4 Therefore, the widely used definition of intrapartum fever (38.0°C) is generally associated with fetal brain temperatures of 39.5°C or higher.Term infants have a low risk of neonatal encephalopathy of approximately 0.12%. 5 The observed risk of encephalopathy with fetal exposure to maternal fever alone is 1.13% and the risk with fetal exposure to acidosis (cord pH <7.05) alone is 1.58%. However, the combination of maternal fever and neonatal acidosis results in a substantial increase in the risk of neonatal encephalopathy to 12.5%, independent of neonatal sepsis. 5 This observation has led to the hypothesis that maternal fever ...