Intrapartum electronic fetal monitoring (EFM) and cord gas analysis do not identify preterm fetuses with fetal inflammatory response syndrome (FIRS)

Abstract

ObjectiveFIRS is associated with an increased risk of neonatal neurologic morbidity. EFM and cord gas analysis were introduced with the expectation of identifying fetuses at risk for neurologic morbidity. We tried to determine if these techniques could identify fetuses with FIRS.Study designFrom 6/99-9/02, 40 infants were born between 28 & 34 weeks at our institution with histologically confirmed chorioamnionitis and funisitis. 40 controls without inflammation were matched for gestational age and mode of delivery. 2 hours of intrapartum fetal heart rate tracing from the end of the 1st stage of labor for vaginal deliveries or immediately prior to delivery for cesareans were analyzed by 2 independent reviewers blinded to fetal outcome.ResultsDecelerations, when analyzed by sub-type (late, early, bradycardia, variables), were still not significantly different between the groups.ConclusionFetuses with FIRS with histologically confirmed chorioamnionitis and funisitis usually have reassuring fetal heart rate tracings and are not identifiable by EFM or cord gas. They exhibit a higher cord pH, baseline FHR, % reactivity, short term variability and accelerations that, although statistically significant, are not clinically significant. Infants at increased risk of neurologic morbidity may not be identified by current surveillance techniques. ObjectiveFIRS is associated with an increased risk of neonatal neurologic morbidity. EFM and cord gas analysis were introduced with the expectation of identifying fetuses at risk for neurologic morbidity. We tried to determine if these techniques could identify fetuses with FIRS. FIRS is associated with an increased risk of neonatal neurologic morbidity. EFM and cord gas analysis were introduced with the expectation of identifying fetuses at risk for neurologic morbidity. We tried to determine if these techniques could identify fetuses with FIRS. Study designFrom 6/99-9/02, 40 infants were born between 28 & 34 weeks at our institution with histologically confirmed chorioamnionitis and funisitis. 40 controls without inflammation were matched for gestational age and mode of delivery. 2 hours of intrapartum fetal heart rate tracing from the end of the 1st stage of labor for vaginal deliveries or immediately prior to delivery for cesareans were analyzed by 2 independent reviewers blinded to fetal outcome. From 6/99-9/02, 40 infants were born between 28 & 34 weeks at our institution with histologically confirmed chorioamnionitis and funisitis. 40 controls without inflammation were matched for gestational age and mode of delivery. 2 hours of intrapartum fetal heart rate tracing from the end of the 1st stage of labor for vaginal deliveries or immediately prior to delivery for cesareans were analyzed by 2 independent reviewers blinded to fetal outcome. ResultsDecelerations, when analyzed by sub-type (late, early, bradycardia, variables), were still not significantly different between the groups. Decelerations, when analyzed by sub-type (late, early, bradycardia, variables), were still not significantly different between the groups. ConclusionFetuses with FIRS with histologically confirmed chorioamnionitis and funisitis usually have reassuring fetal heart rate tracings and are not identifiable by EFM or cord gas. They exhibit a higher cord pH, baseline FHR, % reactivity, short term variability and accelerations that, although statistically significant, are not clinically significant. Infants at increased risk of neurologic morbidity may not be identified by current surveillance techniques. Fetuses with FIRS with histologically confirmed chorioamnionitis and funisitis usually have reassuring fetal heart rate tracings and are not identifiable by EFM or cord gas. They exhibit a higher cord pH, baseline FHR, % reactivity, short term variability and accelerations that, although statistically significant, are not clinically significant. Infants at increased risk of neurologic morbidity may not be identified by current surveillance techniques.