Development of fetal heart rate dynamics before and after 30 and 35 weeks of gestation

In this study, we have investigated how the dynamics of fetal beat-to-beat heart rate variability (fHRV) changes during development prior to 35 weeks and after 30 weeks of gestation. Noninvasive fetal electrocardiogram (ECG) signals from 45 pregnant women at the gestational age from 16 to 41 weeks with normal single pregnancies were analysed. A nonlinear parameter called complex correlation measure (CCM) which measures the variability in the temporal structure of Poincaré plot was used to understand the dynamics of fHRV. Dependency of Results indicate that variability in fetal heart rates as captured by SD1 and SD2 markedly changes after 35 weeks of gestation whereas dynamics in fetal heart rates as captured by CCM substantially changes after 30 weeks of gestation. It might be due to significant amount of maturation of the autonomic nervous system might be done after 30 weeks and before 35 weeks and could potentially help identify the pathological autonomic nervous system development.