Music Modulates Autonomic Nervous System Activity in Human Fetuses

Abstract

Context: Fetal Autonomic Nervous sysTem Evaluation (FANTE) is a non-invasive tool that evaluates the autonomic nervous system activity in a fetus. Autonomic nervous system maturation and development during prenatal life are pivotal for the survival and neuropsychiatric development of the baby.

Objective: Aim of the study is to evaluate the effect of music stimulation on fetal heart rate and specific parameters linked to ANS activity, in particular fetal heart rate variability.

Methods: Thirty-two women between the 32nd and 38th week with a singleton uncomplicated pregnancy were recruited. All FANTE data collections were acquired using a 10-derivation electrocardiograph placed on the maternal abdomen. In each session (5 min basal, 10 min with music stimulus, and 5 min post-stimulus), FANTE was registered. The music stimulus was "Clair de lune" Debussy, played through headphones on the mother's abdomen (CTR: 31927).

Results: Music does not change the mean value of fetal heart rate. However, indices of total fetal heart rate variability statistically increase (RRsd p = 0.037, ANNsd p = 0.039, SD2 p = 0.019) during music stimulation in comparison to the basal phase. Heart rate variability increase depends mainly on the activation of parasympathetic branches (CVI p = 0.013), meanwhile, no significant changes from basal to stimulation phase were observed for indices of sympathetic activity. All the parameters of heart rate variability and parasympathetic activity remained activated in the post-stimulus phase compared to the stimulus phase. In the post-stimulus phase, sympathetic activity resulted in a significant reduction (LFn p = 0.037).

Conclusion: Music can influence the basal activity of the fetal autonomic nervous system, enhancing heart rate variability, without changing fetal heart rate mean value. Music is enabled to induce a relaxation state in a near-to-term fetus, mediated by parasympathetic activation and by a parallel sympathetic inhibition.

Keywords: autonomic nervous system evaluation; fetal autonomic nervous system; fetal nervous system; heart rate variability (HRV); musical stimulation; non-invasive evaluation.

FIGURE 1

Scheme of 10 electrodes placed on the maternal abdomen during musical stimulation.

FIGURE 2

Fetal heart rate mean (A) and heart rate variability, expressed ad RRsd (B) during FANTE data collection. pre, basal FANTE data collection; stimulus, stimulus FANTE data collection; post, post-stimulus FANTE data collection. *significant at the alpha level p < 0.05; **significant at the alpha level p < 0.01.

FIGURE 3

The impact of musical stimulation on index-linked to ANS activity. (A) ANNsd (ms): standard deviation of the Average NN; (B) SD (ms): standard deviation perpendicular to the line of the identity of Poincairè Plot; short term variability, mainly controlled by parasympathetic tone; (C) Ptot (ms2): total power of fetal RR series, index of total HRV, mainly controlled by sympathetic tone; (D) CVI (ms2): Cardiac Vagal Index, the contribution of the parasympathetic nervous system to cardiac regulation; (E) LFn: low-frequency band (0.04–0.15 Hz) normalized for the total power; low-frequency band mainly controlled by sympathetic tone; pre: basal FANTE data collection; stimulus: stimulus FANTE data collection; post; post-stimulus FANTE data collection. *significant at the alpha level p < 0.05; **significant at the alpha level p < 0.01.

FIGURE 4

Persistent short-term musical modulation of ANS activity. (A) ANNsd (ms): standard deviation of the Average NN; (B) SD (ms): standard deviation perpendicular to the line of the identity of Poincairè Plot; short term variability, mainly controlled by parasympathetic tone; (C) Ptot (ms2): total power of fetal RR series, index of total HRV, mainly controlled by sympathetic tone; (D) CVI (ms2): Cardiac Vagal Index, the contribution of the parasympathetic nervous system to cardiac regulation; (E) LFn: low-frequency band (0.04–0.15 Hz) normalized for the total power; low-frequency band mainly controlled by sympathetic tone; pre: basal FANTE data collection; stimulus: stimulus FANTE data collection; post; post-stimulus FANTE data collection. *significant at the alpha level p < 0.05; **significant at the alpha level p < 0.01.