Tone entropy analysis of foetal heart rate variability

Ahsan Khandoker, Chandan Karmakar, Yoshitaka Kimura, Miyuki Endo, Sayaka Oshio, Marimuthu Palaniswami

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Development of the foetal autonomic nervous system can be indirectly understood by looking at the changes in beat to beat variability in foetal heart rates. This study presents Tone-Entropy (T-E) analysis of foetal heart rate variability (HRV) at multiple lags (1-8) to understand the influence of gestational ages (early and late) on the development of the foetal autonomic nervous system (ANS). The analysis was based on foetal electrocardiograms (FECGs) of 46 healthy foetuses of 20-32 weeks (early group) and 22 foetuses of 35-41 weeks (late group). Tone represents sympatho-vagal balance and entropy the total autonomic activities. Results show that tone increases and entropy decreases at all lags for the late foetus group. On the other hand, tone decreases and entropy increases at lags 1-4 in the early foetus group. Increasing tone in late foetuses might represent significant maturation of sympathetic nervous systems because foetuses approaching to delivery period need increased sympathetic activity. T-E could be quantitative clinical index to determine the early foetuses from late ones on the basis of maturation of autonomic nervous system.

Original languageBritish English
Pages (from-to)1042-1053
Number of pages12
Issue number3
StatePublished - 2015


  • Foetal autonomic nervous system
  • Foetal electrocardiogram
  • Foetal heart rate variability
  • Tone-Entropy analysis


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