Quantification of the Fetal Heart Rate Variability by Spectral Analysis in Growth-Retarded Fetuses

Abstract

The analysis of short-term variability of fetal heart rate in the frequency domain was performed. The fetal activity states (quiescence, trunk rotation, body movements, fetal breathing movements) were taken into account. The differences between the shapes of power spectra in physiological and growth-retarded fetuses were discussed.

Linear analysis of fetal magnetocardiogram recordings in normal pregnancies at various gestational ages

“…As the frequency components, corresponding to the normal physiological mechanisms of the FHR, have been identified, any deviations in the power spectra could be an indication of pathology. In previous studies a differentiation in the power spectra of FHR variability in pregnancies complicated by diabetes mellitus (Ropacka et al, 2000), IUGR (Breborowicz et al, 1988;Ropacka et al, 2000), hypertension and hypoxia (Oppenheimer and Lewinsky, 1994;Rassi and Lewis, 1995) has been reported. In this study we did not observe any deviation in the spectra that could be correlated with an unfavorable pregnancy outcome (Table 1).…”

“…Analysis of the frequency content at various stages of gestation provides information on the fetal sympathovagal balance and assesses the fetal growth and development. Pathological conditions such as diabetes mellitus, intrauterine growth retardation, hypertension and hypoxia that could possibly affect FHR might also influence power spectra (Oppenheimer and Lewinsky, 1994;Rassi and Lewis, 1995;Breborowicz et al, 1988;Ropacka et al, 2000). The frequency components were identified in two bands: one high frequency band (HF), between 0·15 and 0·4 Hz, around the respiratory frequency (RSA) and one low frequency band (LF) between 0·04 and 0·15 Hz, which is mediated by the sympathetic system and is attributed to Mayer waves.…”

Marked fetal acidosis and specific changes in power spectrum analysis of fetal heart rate variability recorded during the last hour of labour

“…In our study, gestational age showed no association with low‐frequency or total fetal heart rate variability probably because only pregnancies over 35 weeks were included. Fetal movements may increase low‐frequency fetal heart rate variability, but there have also been contradictory results 24,25 . During delivery, fetal movements decrease and, when they do occur, they are mostly associated with uterine contractions 26,27 .…”

Power spectrum analysis of heart rate and blood flow velocity variability measured in the umbilical and uterine arteries in early pregnancy: a comparative study

“…We measured umbilical and uterine flow velocity waveforms at 10 -20 weeks of gestation to determine both maternal and fetal heart rate variability and flow velocity variability as parameters of functional control of the autonomic nervous system 12 . The aim of the study was to establish maternal and fetal variability in heart rate and blood flow velocity to compare developing and mature systems for autonomic regulation of cardiovascular function.…”