Uncorrected Author Proof Journal of Neonatal-Perinatal Medicine xx (20xx) x–xx DOI:10.3233/NPM-180044 IOS Press 1 Original Research 1 Characteristics of fetal and maternal heart rate tracings during labor: A prospective observational study 2 3 4 M.K. Ramadan a,b , R. Fasih a , S. Itani a , G.R. Salem Wehbe b,c and D.A. Badr b,c,∗ 5 a Department of Obstetrics and Gynecology, Makassed General Hospital, Beirut, Lebanon 6 b Department of Obstetrics and Gynecology, Lebanese University, Beirut, Lebanon 7 c Department of Obstetrics and Gynecology, Universit ´ e Libre de Bruxelles (FOSFOM), Belgium 8 Received 4 April 2018 9 Revised N/A 10 Accepted 8 March 2019 11 Abstract. 12 BACKGROUND: Fetal well-being is assured during labor and delivery with the employment of electronic fetal heart monitoring (EFHM). In uncommon instances, maternal heart rate (MHR) instead of fetal heart rate (FHR) can be the source of signals on monitors (signal ambiguity) leading to erroneous interpretation and management. Information about MHR characteristics are comparatively inadequate. We aim to analyze and compare MHR and FHR characteristics during the first and second stages of labor. 13 14 15 16 17 METHODS: A prospective cohort study was conducted in a single tertiary care center during a one year period. Fifty one healthy full term women with singleton pregnancies during labor were enrolled. Uterine contractions, MHR and FHR were recorded simultaneously during both stages of labor by monitors designed for twin gestation. 18 19 20 RESULTS: When compared to FHR, MHR had significantly lower baseline rate during 1st and 2nd stages (p < 0.0001). It demonstrated also more marked beat-to-beat variability during both stages (p < 0.0001). MHR showed significantly more accelerations (p = 0.03 and p = 0.008) and less decelerations (p < 0.0001 and p = 0.021) during 1st and 2nd stages respectively. 21 22 23 CONCLUSIONS: All characteristic parameters and patterns produced by FHR could be mimicked by MHR as well, though, at different frequencies. Understanding EFHM patterns suspected to be MHR artefacts and the employment of modern monitors that simultaneously obtain and display FHR and MHR can unmask ambiguity and avert related misinterpretation problems. Similar studies should be conducted in high-risk groups where the potential for fetal hypoxia/acidosis is increased. 24 25 26 27 Keywords: Cardiotocogram, fetal heart rate, intrapartum monitor, maternal heart rate, signal ambiguity 28 1. Introduction 29 EFHM has been in clinical use for the past 50 years 30 and is considered the standard of intrapartum care [1]. 31 ∗ Address for correspondence: Dominique A. Badr, MD, Leopold I, 335/0001, Jette 1090, Brussel, Belgium. Tel.: +32486172228; E-mail: dominiquebader@hotmail.com. Its significance stems from two elements: first, it per- 32 mits surveillance of fetal well-being during labor and 33 delivery and second, it helps early identification of 34 fetal jeopardy, thus, allowing timely interventions by 35 either alleviating harmful exposures or removing the 36 fetus by performing expeditious delivery (including 37 emergent cesarean section) [1]. In some instances, 38 however, a signal ambiguity may occur and this is 39 1934-5798/19/$35.00 © 2019 – IOS Press and the authors. All rights reserved