553 Distinguishing true from false labor with a novel labor test

Abstract

Traditional tocodynamometry (toco) qualitatively displays any uterine activity as a contraction but cannot distinguish between synchronized labor contractions and “false” labor. Uterine electromyography (uEMG) has the ability to characterize the nuanced differences in underlying bioelectrical activity, allowing physiologic correlation. We developed a labor test using serial analyses of 2 independent uEMG indices. Our objective was to use this test to distinguish true and false labor in subjects with contractions. Prospective observational study of 22 subjects with singleton pregnancies > 30 weeks gestational age who presented for evaluation of self-reported, regular contractions. Subjects were excluded if cervical dilation was ≥ 3 cm. Six-channel uEMG recordings were obtained using proprietary directional EMG sensors applied on the abdomen for ∼ 60 minutes. An artificial intelligence algorithm calculated a contraction synchronization index (CSI) and a false labor signal (FLS) index for each subject. uEMG indices were serially combined to create a labor test (Figure 1); CSI > 2.0 or CSI 1.0 - 2.0 (indeterminate) + FLS < 3 defined true labor. Gold standard for true labor was delivery ≤ 24 hours. Primary outcome measures were test sensitivity and specificity. Our labor test correctly identified labor status for 19 subjects (Figure 2). One had CSI > 2.0 and delivered ≤ 24 hours of assessment. Eighteen were identified as having either CSI ≤ 1 or indeterminate CSI + FLS > 3 and delivered > 24 hours from assessment. Three subjects who were predicted to have false labor (SF < 1.0) delivered ≤ 24 hours from assessment. The sensitivity of this labor test is 25%, specificity is 100%. Our labor test demonstrates that uEMG signal analysis can be used to distinguish true from false labor. The labor test had high specificity for determining labor status in subjects presenting with regular contractions. The clinical applicability of this diagnostic tool could have a significant impact on the medical management of patients in whom labor is uncertain.View Large Image Figure ViewerDownload Hi-res image Download (PPT)