Magnetographic assessment of fetal hiccups and their effect on fetal heart rhythm

Abstract

Fetal hiccups emerge as early as nine weeks post-conception, being the predominant diaphragmatic movement before 26 weeks of gestation. They are considered as a programmed isometric inspiratory muscle exercise of the fetus in preparation for the post-natal respiratory function, or a manifestation of a reflex circuitry underlying the development of suckling and gasping patterns. The present paper provides the first evidence of non-invasive biomagnetic measurements of the diaphragm spasmodic contractions associated with fetal hiccups. The magnetic field patterns generated by fetal hiccups exhibit well-defined morphological features, consisting of an initial high frequency transient waveform followed by a more prolonged low frequency component. This pattern is consistent across recordings obtained from two fetal subjects, and it is confirmed by signals recorded in a neonatal subject. These results demonstrate that fetal biomagnetometry can provide insights into the electrophysiological mechanisms of diaphragm motor function in the fetus. Additionally, we study the correlation between hiccup events and fetal cardiac rhythm and provide evidence that hiccups may modulate the fetal heart rate during the last trimester of pregnancy.

Effects of docosahexaenoic acid supplementation during pregnancy on fetal heart rate and variability: A randomized clinical trial

“…We used a template-matching algorithm developed by our team [23] in EEGLab 4.311 [19] to automatically detect R-peaks for time- and frequency-domain analysis. False positive and false negative detections and abnormal beats were manually corrected to create an interbeat interval (IBI) series from the MCG data.…”

Fetal cardiac autonomic control during breathing and non-breathing epochs: The effect of maternal exercise

“…We also used a template-matching algorithm developed by our team (15) in EEGLab 4.311 (10) to automatically detect R-peaks for frequency domain analysis. False positive and false negative detections and abnormal beats were manually corrected.…”

Regular Maternal Exercise Dose and Fetal Heart Outcome

“…All 18-min multivariate data recordings were presented to an Infomax independent component analysis algorithm implemented in the EEGLAB toolbox, free download from University of California San Diego, (12) to segregate matemal magnetocardiogram (MCG), fetal magnetocardiogram, and various fetal movements with distinct and previously characterized biomagnetic signatures (18,37,38). The fetal magnetocardiogram was identified and fiducial R peaks were automatically detected using a template-matching algorithm designed by our team to generate the interbeat-interval time series (18,26,37,38). All MCG traces were manually checked (L.E.M., K.M.G.)…”