Fetal development of complex autonomic control evaluated from multiscale heart rate patterns

Area of Science:

• Fetal Physiology
• Neuroscience
• Biomedical Engineering

Background:

• Fetal heart rate patterns reflect autonomic nervous system (ANS) development.
• Conventional ANS indices inadequately capture the complex interplay between sympathetic and vagal rhythms.
• Universal behavioral indices may offer deeper insights into maturating autonomic control.

Purpose of the Study:

• To investigate fetal autonomic control maturation using magnetocardiography.
• To analyze fetal heart rate complexity and rhythms in active and quiet states across gestational ages.
• To evaluate the utility of multiscale entropy and other complexity measures for assessing fetal development.

Main Methods:

• Fetal magnetocardiography recordings (10-min intervals) from 359 fetuses (22–39 wk gestational age).
• Analysis of standard deviation of heartbeat intervals, skewness, power spectrum, and multiscale entropy.
• Linear regression used to analyze age dependence in active and quiet states.

Main Results:

• In the quiet state, sympathovagal rhythm contribution and complexity increased with gestational age, with skewness shifting from negative to positive.
• In the active state, age dependencies were less pronounced, but skewness and fluctuation amplitude increased.
• Multiscale entropy methodology was validated for 10-min fetal magnetocardiography datasets.

Conclusions:

• Stable, complex autonomic rhythms develop in the quiet fetal state.
• The active fetal state exhibits increasing behavioral variability influenced by internal and external factors.
• State-selective assessment combined with complexity measures can enhance prenatal diagnosis of developmental issues.