401 Amplitude-modulation of maternal electrocardiography and phonocardiography as a novel method for wireless non-invasive uterine monitoring

Abstract

Uterine activity (UA) monitoring is an essential element of pregnancy management. The gold standard intrauterine pressure catheter (IUPC), is invasive and requires ruptured membranes. Conventional, external tocodynamometry (TOCO) is hampered by obesity, maternal movements, and belt positioning, with positive agreement rates (PA) as low as 54-73% and false detection rates (FDR) as high as 15-32%. We prospectively tested a novel algorithm that enables non-invasive and reliable detection of UA. A prospective, comparative, open label, multicenter study was conducted, in which 40 laboring women (≥32 weeks; BMI<50) were simultaneously monitored for 30-60 minutes with IUPC and INVU (Nuvo Group), a wireless device FDA-cleared for remote fetal and maternal heart rate monitoring. Ten subjects were monitored with TOCO as well. UA detection by INVU was based on the modulation of the maternal electrocardiographic and phonocardiographic signals. 3 blinded assessors marked the contractions for each modality. PA and FDR of INVU and TOCO compared to IUPC were calculated. Overall, INVU correctly identified 87.7% of the IUPC contractions. Sub-analysis based on BMI categories (normal: <25, overweight: 25-30, obese: ≥30) showed that UA detection was not affected by BMI (PA: 88.5%, 85.9% and 90.0%, respectively; p=0.42). Overall, INVU FDR was 15.2%. In the subset of sessions recorded with TOCO, TOCO PA and FDR were 46% and 7.1% respectively. UA monitoring via INVU is accurate and reliable, even in obese women, and more precise than TOCO. There is a pressing need for telehealth solutions in pregnancy monitoring, underscored by the current COVID-19 pandemic. INVU (Nuvo Group) is a self-administered device, FDA-cleared for wireless, remote monitoring of fetal and maternal heart rate. This novel method for UA detection via INVU expands its remote pregnancy monitoring capabilities to include surveillance such as non-stress tests, which would be of great benefit to women and providers seeking telehealth solutions for high risk pregnancy care.