A mother's voice plays a crucial role in early child development, particularly for the health of premature babies, suggests the findings of a French study.
A review of 15 studies involving 512 preterm infants born between 2000-2015 found hearing the maternal voice, either recorded or live, appears to play a role in stabilising the infants.
It was linked with physical and behavioural benefits as well as fewer cardiorespiratory events, according to the review published in journal Acta Paediatrica.
"Preterm infants' state becomes more stable when mothers talk and sing to them, with potential clinical benefits on autonomous nervous system maturation," said lead author Dr Manuela Filippa from University of Paris Ouest Nanterre.
However, there was insufficient evidence to evaluate the long-term impact of the maternal voice, the authors noted.
In seven studies, the authors reported benefits in the physiological domain.
More specifically, a decrease in heart rate was observed in two studies with recorded maternal voices, an increase in heart rate was reported in one study with live maternal voices, and significant decreases in cardiorespiratory events were observed in two studies.
A decrease in oxygen saturation and in respiration rate were reported in two studies after the intervention.
Five studies provided evidence of the effects of the maternal voice on behaviour, including alertness and the opening of eyes, and one study even reported changes in the brain.
The "encouraging" findings indicate the maternal voice has beneficial effects on the infant's stability, wrote the authors.
"In particular, maternal voice interventions seemed to support preterm infants' systemic oxygenation and, relevantly, to diminish the occurrence of critical respiratory events, such as episodes of bradycardia and apnoeas," wrote the authors.
Cardiorespiratory stability is crucial for all preterm infants, in particular for very and extremely low-birthweight infants.
The sooner it is reached, the earlier the preterm infant is able to tolerate drug administered feeding.
Dr Filippa and her co-authors suggest the evidence support the beneficial effects of maternal vocal interventions, in particular infants born before 32 weeks.
