325 - Maternal Heart Rate Variability as a Predictor of Intrapartum Fever

Poster Number: 325
Publication Number: 325.439

Shubham Debnath, The Feinstein Institutes for Medical Research, Manhasset, NY, United States; Robert Koppel, Division of Neonatal-Perinatal Medicine, Cohen Children’s Medical Center, Northwell Health and Zucker School of Medicine at Hofstra/Northwell, New Hyde Park, NY, United States; Barry Weinberger, Division of Neonatal-Perinatal Medicine, Cohen Children’s Medical Center, Northwell Health and Zucker School of Medicine at Hofstra/Northwell, New Hyde Park, NY, United States; Theodoros P. Zanos, Feinstein Institutes for Medical Research, Manhasset, NY, United States

Background: Heart rate variability (HRV) is defined as beat-to-beat fluctuation of the R-R interval and serves as a marker of autonomic nervous system function. Alterations in neonatal HRV have been validated as a predictor of sepsis in newborns. Similarly, HRV for women in labor may be affected by impending maternal-fetal infection.

Objective: We hypothesize that alterations in the HRV of women during labor precede the onset of intrapartum fever, which is the most significant risk factor for neonatal sepsis.

Design/Methods: Continuous temperature, heart rate, and beat-to-beat R-R intervals were recorded from women (n=141) during labor using wireless sensors (Isansys, Oxford, UK), and vital signs were measured manually every 3-6 hours. HRV was calculated in moving 5-minute windows of R-R intervals using two validated measures: standard deviation of normal-to-normal intervals (SDNN) and root mean square of successive differences (RMSSD) between normal heartbeats.

Results: Fever (> 38.0°C) was detected by manual or continuous measurements in 48 women (“febrile” group); the other 93 women comprised the “afebrile” group. Time 0 was defined as the onset of fever for the febrile group, and 2.4 hours prior to delivery for the afebrile group, corresponding to the mean time of fever onset in the febrile group. Compared to afebrile mothers, the average HRV (both SDNN and RMSSD) in febrile mothers decreased significantly at 2-3 hours before Time 0 (Fig. 1, ANOVA p < 0.001).Conclusion(s): Wireless continuous HRV measurements are feasible during labor. Maternal HRV decreases between 2 and 3 hours prior to the onset of intrapartum fever and may be useful for building a predictive model for neonatal sepsis. We speculate that HRV-based fever predictive models will be feasible and useful for guiding maternal antibiotic prophylaxis. Earlier identification of infants at risk for early onset sepsis may also facilitate postnatal diagnostic and therapeutic interventions to improve outcomes.
Average Maternal Heart Rate Variability During LaborShown are two validated measures of heart rate variability (HRV) during labor calculated in moving 5-minute windows of R-R intervals: standard deviation of normal-to-normal intervals (SDNN, above), and root mean square of successive differences (RMSSD, below) between normal heartbeats. In both plots, orange represents the febrile group (n = 48) and blue represents the afebrile group (n = 93); the bold line shows the average with shaded bands for standard error. Time 0 was defined as the onset of fever for the febrile group and 2.4 hours prior to delivery for the afebrile group, corresponding to the mean time of fever onset in the febrile group. Compared to afebrile mothers, the average HRV (both SDNN and RMSSD) in febrile mothers decreased significantly at 2-3 hours before time 0 (p < 0.001).