128: Comparison of fetal ECG and standard external Doppler monitoring performance during second stage of labor

Abstract

Maternal expulsive efforts may result in loss of fetal heart rate (FHR) monitoring data, potentially leading to unrecognized fetal compromise. We sought to determine if an external fetal electrocardiogram (fECG) monitoring device could provide more interpretable FHR data during the second stage of labor compared to standard external Doppler monitoring (SEM). Secondary analysis of a randomized controlled trial at 4 Utah hospitals. Patients with singleton, term pregnancies, were enrolled at labor admission and randomized in blocks based on body mass index (BMI) to fECG or SEM. Women were included in this analysis if they reached the second stage of labor while remaining on assigned study device (fECG or SEM). The primary outcome for this analysis was the proportion of interpretable 10-minute FHR tracing segments during the second stage of labor, where tracings were evaluated by two reviewers blinded to study device allocation. Tracing segments were deemed interpretable if FHR baseline and periodic changes could be discerned. The proportion of total interpretable minutes of FHR tracing was also evaluated. A mixed effects logistic regression model was fit to predict 10 and 1-minute FHR tracing segment interpretability. Study arm, labor stage, and interaction between device and labor stage were included in the model. Of the 218 women randomized in the initial study, 50 women in the fECG group and 67 in the SEM group reached the second stage of labor while remaining on their originally assigned study device. Maternal demographics and clinical outcomes were similar between arms. fECG generated significantly more interpretable 10-minute segment FHR data in the second stage, where fECG use resulted in almost double the amount of interpretable 10-minute FHR tracing segments compared to SEM (Figure 1). Similar findings were noted in the 1-minute segment FHR tracing analysis (Figure 2). These findings highlight the clinical utility of fECG, particularly during the second stage of labor, when FHR tracing signal quality is often compromised.View Large Image Figure ViewerDownload Hi-res image Download (PPT)