864: Uterine Fasciculation-Like Signals: A novel pattern of uterine bioelectric activity

Abstract

Here we present a novel uterine electromyography (uEMG) signal (Figure 1). This signal indicates prolonged uterine muscle activity rather than phasic activity; thus, we have named them Fasciculation-Like Signals (FLS). FLS may have been overlooked in previous research because of reliance on ECG pads rather than directional EMG sensors. The objective of this study is to determine the prevalence of FLS in patients presenting to labor and delivery with contractions. This is a prospective observational study of women with singleton pregnancies between 30w0d and 36w6d who presented to labor and delivery for evaluation of contractions. Six-channel uEMG recordings were obtained using directional EMG sensors for > 60 minutes. Uterine signals were isolated using a bandpass filter between 0.15 and 1.2 Hz to isolate uterine signals. The 10 minute period of the recording with the greatest bioelectrical activity was identified visually. A computer algorithm was then used to identify the total length of time where root mean squared (RMS) exceeded resting RMS by 2.5-fold. The FLS duration for each channel was calculated by subtracting the duration of contraction-associated signals (characteristic EMG signals associated with uterine contractions), if any, within the window. FLS were scored on a scale of 0 to 4, where 0 represents no FLS seen, and 4 represents 5 to 6 channels simultaneously reporting FLS. (Figure 2 contains complete scoring rules). Eight subjects were included, with one subject studied twice at 32w0d and 33w5d (total n=9 studies). None of the patients delivered within 7 days of their evaluation. All 7 recordings performed < 36w0d had an FLS ≥ 2. One subject with FLS score=2 delivered preterm. Complete outcomes data is shown in Figure 2. Fasciculation-Like Signals are a newly described pattern of uterine bioelectric activity. These signals may explain the biomechanics of prodromal contractions, especially if similar signals were not seen during labor. If confirmed, the presence of FLS may serve a novel test to rule-out preterm labor.View Large Image Figure ViewerDownload Hi-res image Download (PPT)