Comment on the article “Accuracy and reliability of fetal heart rate monitoring using maternal abdominal surface electrodes”

Abstract

Comment on the article "Accuracy and reliability of fetal heart rate monitoring using maternal abdominal surface electrodes" Sir, We found the article by Cohen et al. in the November issue of AOGS, regarding fetal heart function monitoring with electrodes placed on the abdomen of a pregnant woman during labor (fetal electrocardiography), very interesting (1). We are particularly interested in the ratio of cases in which achievement of an electric signal from the fetal heart was successful enough for it to be read, recorded and evaluated; and therefore satisfactory for application of the method for antelabor and intralabor monitoring of the fetal condition. In a study at our center we applied transabdominal monitoring to 612 women between 28 and 42 weeks of gestation in an uncomplicated pregnancy, and in 91 cases of a pregnancy complicated by fetal intrauterine growth restriction or pregnancy-induced hypertension, as well as in 84 cases complicated by imminent preterm delivery. Examinations were performed using the KOMPOREL â system (ITAM, Zabrze, Poland), with an electrode placement scheme almost identical to the scheme applied in the Santa Monica system (2). The mean value of electric signal loss was 32%. This value is comparable with those reported by Cohen et al. and obtained during monitoring on the first stage of delivery, which may be assumed to be similar to the conditions for examination applied by our team. However, in many cases the loss was much more pronounced. From the practical point of view, a loss of fetal heart rate signals in between 20% and 30% of cases, results in a cardiotocography record quality that makes any interpretation of results of the examination impossible. FIGO recommendations mention 20% as an acceptable signal loss (3). In our material we did not find any correlation between the value of signal loss and body mass index of the pregnant women. A slightly better ratio of patients with loss below 20% during the first stage of the delivery has been presented by Reinhard et al.; however, there were only 144 patients included in the study (4). In our opinion, application of transcutaneous fetal electrocardiography as a method of fetal heart rate monitoring may be limited both before and during delivery, because of the impossibility of foreseeing the value of signal loss, which hinders or even makes impossible proper fetal supervision. References 1. Cohen WR, Ommani S, Hassan S, Mirza FG, Solomon M, Brown R, et al. Accuracy and reliability of fetal heart rate monitoring using maternal abdominal surface electrodes. Acta Obstet Gynecol Scand 2012;91(11):1306-13. 2. Fuchs T, Pomorski M, Grobelak K, Tomiałowicz M, Zimmer M. Signal loss during fetal heart rate monitoring using maternal abdominal surface electrodes between 28 and 42 weeks of pregnancy. Ginekol Pol 2013; In Press. 3. Rooth G, Huch A, Huch R. Guidelines for the use of fetal monitoring. Int J Gynaecol Obstet 1987;25(3):159-67. 4. Reinhard J, Hayes-Gill BR, Schiermeier S, Hatzmann W, Herrmann E, Heinrich TM, et al. Intrapartum sig...