336: Effects of intrapartum fever on umbilical artery pH, lactate and base excess

Abstract

Both elevated umbilical artery (UA) lactate and maternal fever have been independently associated with poor neonatal outcomes, including acidosis, hypoxic-ischemic encephalopathy, cerebral palsy, etc. We sought to determine whether maternal intrapartum fever had an impact on neonatal metabolic status, as determined by UA pH, lactate and base-excess. In this prospective cohort study, UA cord blood samples were collected from vaginal and cesarean singleton deliveries that occurred between June and August 2019 at a tertiary care center. UA pH, lactate and base excess were then assessed using a GEM 4000 blood gas analyzer. Presence of maternal intrapartum fever (temperature > 31.5°C or 100.5°F during labor) were determined from medical records. 205 samples were included in the study. There was no statistically significant difference in UA pH between births complicated by maternal fever (n=9, mean pH 7.20) and those not complicated by fever (n=196, pH 7.23, p=0.328). However, the mean UA lactate in the maternal fever group was significantly higher than that of the non-fever group (6.04 mmol/L vs. 4.47 mmol/L, respectively, p=0.002). Mean base excess was also significantly lower in the maternal fever group (-7.87 mEq/L vs. -5.45 mEq/L in the non-fever group, p=0.0142). Though UA pH did not differ between the groups, neonates born to mothers with intrapartum fevers were found to have significantly higher UA lactate and lower base excess than those born to mothers who remained afebrile at delivery. This suggests the presence of fetal metabolic challenge that would not have been evident when only using UA pH as an assessment of neonatal metabolic status. Further research is needed to determine the clinical significance of these findings with respect to neonatal outcomes.