(782) Phenotyping Labor Dystocia: A Pilot Study Triangulating Cytokines and Uterine EMG Parameters

In this prospective pilot, we measured IL-6 at ~37 weeks gestation and upon admission for labor and analyzed a 30-minute segment of uterine electromyography (EMG) during labor using the 128hz 12bit Lovelace FT device (Bloomlife) in (N = 8) low-risk nulliparas planning vaginal birth. The three EMG channels were band pass filtered between 0.1 and 1 Hz using a second order Butterworth filter, then adaptively combined based on their signal-to-noise ratio. The output was then down-sampled at 16 Hz and normalized and the mean contraction duration and power density spectrum (PDS) median and peak frequency were calculated for each contraction.

Results: Change in IL-6 from enrollment to admission was associated with the EMG PDS peak frequency (Spearman’s Rho = .593, p = .044); admission IL-6 also trended toward correlation with EMG PDS peak frequency (Spearman’s Rho = .733, p = .079) (Figure 1). Although not statistically significant, IL-6 on admission, change in IL-6, and EMG PDS peak frequency were lower in those with induction, dystocia, and cesarean.

Conclusion:

Generalizability is limited by small sample size, multiple exploratory comparisons, and incomplete timing data to link the EMG data to labor events. Despite the limitations of the data, the significant association between EMG PDS peak frequency and IL-6 supports our original hypothesis and suggests that IL-6 may have a role in uterine contractility during labor. Researchers can improve quality of intrapartum EMG data by reducing skin impedance < 10kOhms, utilization of hardware to log accelerometer data and electrode locations, and real-time synchronous logging of the labor events (including medications).