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

In this study we investigated the fetal magnetocardiogram recordings (FMCG) in 64 women, 21-30 years old, with single normal pregnancies and gestational ages 28-40 weeks. Spectral analysis was used to quantify heart rate variability and to identify the maturation of the autonomic nervous system. According to our results, there was an increase of the ratio LF/HF of the power spectrum, which reflects the maturation of the autonomous nervous system and also an increase in heart rate variability in the course of pregnancies, which was statistically significant (ANOVA test, P < 0.0005) comparing the R-R intervals of the number of cases in the four groups of 28-30, 37-40, 31-33 and 37-40 weeks of gestation. This study highlights some of the advantages of FMCG as a novel, non-invasive technique for obtaining useful clinical information.