Similarities between maternal and fetal RR interval tachograms and their association with fetal development

Namareq Widatalla; Ahsan Khandoker; Mohanad Alkhodari; Kunihiro Koide; Chihiro Yoshida; Yoshiyuki Kasahara; Yoshitaka Kimura; Masatoshi Saito

doi:10.3389/fphys.2022.964755

Similarities between maternal and fetal RR interval tachograms and their association with fetal development

Front Physiol. 2022 Nov 21:13:964755. doi: 10.3389/fphys.2022.964755. eCollection 2022.

Authors

Namareq Widatalla¹, Ahsan Khandoker², Mohanad Alkhodari^{2

3}, Kunihiro Koide⁴, Chihiro Yoshida⁴, Yoshiyuki Kasahara^{1

4}, Yoshitaka Kimura^{1

4}, Masatoshi Saito^{1

4}

Affiliations

¹ Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan.
² Healthcare Engineering Innovation Center, Department of Biomedical Engineering, Khalifa University, Abu Dhabi, United Arab Emirates.
³ Cardiovascular Clinical Research Facility, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.
⁴ Tohoku University Graduate School of Medicine, Sendai, Japan.

Abstract

An association between maternal and fetal heart rate (HR) has been reported but, so far, little is known about its physiological implication and importance relative to fetal development. Associations between both HRs were investigated previously by performing beat-by-beat coupling analysis and correlation analysis between average maternal and fetal HRs. However, studies reporting on the presence of similarities between maternal and fetal HRs or RR intervals (RRIs) over the short term (e.g., 5-min) at different gestational ages (GAs) are scarce. Here, we demonstrate the presence of similarities in the variations exhibited by maternal and fetal RRl tachograms (RRITs). To quantify the same similarities, a cross-correlation (CC) analysis between resampled maternal and fetal RRITs was conducted; RRITs were obtained from non-invasive electrocardiogram (ECG). The degree of similarity between maternal and fetal RRITs (bmfRRITs) was quantified by calculating four CC coefficients. CC analysis was performed for a total of 330 segments (two 5-min segments from 158 subjects and one 5-min from 14 subjects). To investigate the association of the similarity bmfRRITs with fetal development, the linear correlation between the calculated CC coefficients and GA was calculated. The results from the latter analysis showed that similarities bmfRRITs are common occurrences, they can be negative or positive, and they increase with GA suggesting the presence of a regulation that is associated with proper fetal development. To get an insight into the physiological mechanisms involved in the similarity bmfRRITs, the association of the same similarity with maternal and fetal HR variability (HRV) was investigated by comparing the means of two groups in which one of them had higher CC values compared to the other. The two groups were created by using the data from the 158 subjects where fetal RRI (fRRI) calculation from two 5-min ECG segments was feasible. The results of the comparison showed that the maternal very low frequency (VLF) HRV parameter is potentially associated with the similarity bmfRRITs implying that maternal hormones could be linked to the regulations involved in the similarity bmfRRITs. Our findings in this study reinforce the role of the maternal intrauterine environment on fetal development.

Keywords: fetal developement; fetal programming; heart rate vaiability; maternal-fetal RRI similarity; very low frequency.