Key messages
• Music and vocal interventions probably reduce heart rates in preterm infants compared to standard care during the intervention. This beneficial effect was even more substantial and confident after the intervention suggesting a long-lasting relaxing and stabilising effect.
• We found no harmful effects from music and voice. However, many studies did not explicitly explore the possibility of unwanted effects.
• We found no evidence of any other clear beneficial or harmful effects of the interventions on the infants, their parents, and parent-infant bonding. More good-quality evidence is needed to draw further clear conclusions.
What is a preterm infant?
Preterm infants are newborns born before the gestational age of 37 weeks and often have to be treated for weeks to months in the stressful environment of a neonatal intensive care unit to survive.
Why examine the potential benefits of music and vocal interventions for preterm infants and their parents?
Preterm infants are at risk for various health issues. Preterm birth is a traumatic event for the parents as well. Therefore, complementary approaches such as music and vocal interventions are increasingly used in neonatal care to improve physical and mental health in preterm infants and their parents. However, various studies and reviews show ambiguous results in the efficacy of a variety of music and vocal interventions. A more comprehensive and rigorous systematic review is needed to address conflicting data and reviews.
What did we want to find out?
We wanted to find out if music and vocal interventions benefit:
• the health and development of the preterm infant
• the mental health of the parents and their bonding with the infant
We wanted to know which types, delivery, duration, and frequency of music and vocal interventions would best support infants and parents. We aimed to find out if the intervention can cause any harmful effects.
What did we do?
We searched for studies that compared:
• music and vocal interventions for preterm infants (and parents) compared to usual standard care in the neonatal unit that did not include any music or vocal interventions.
We compared and summarised their results and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We found 25 studies that involved 1532 preterm infants and 691 parents. The biggest study was in 272, and the smallest was in 17 preterm infants. Within the studies from around the world, mainly the immediate effect of music and voice was examined in the moments of intervention and minutes post-intervention, whereas two studies wanted to know if there would be a beneficial effect on long-term development at two years. Most studies were funded by University/Health Department/Hospital research funds and local medical/health foundations. The reported music and vocal interventions varied widely in type, delivery, frequency, and duration. They were mainly characterised by calm, soft, musical parameters in lullaby style, often integrating the mother's voice live or recorded, defined as music therapy when provided by a music therapist within a therapeutic relationship or music medicine when delivered as "medicine" by medical and healthcare professionals.
Main results
In preterm infants (and their parents), compared to standard care without any music and vocal interventions:
• Music and voice make no difference to the oxygen saturation during the intervention (10 studies with 958 infants) and may make no difference after the intervention (7 studies with 800 infants).
• Music and voice may make no difference in the respiratory rate during the intervention (7 studies with 750 infants) and after the intervention (5 studies with 636 infants).
• Music and voice may lead to a beneficial reduction in infants' heart rates (11 studies with 1014 infants). This beneficial effect was even more substantial and confident after the intervention, leading to a medium-to-large beneficial reduction in the heart rate (5 studies with 636 infants).
• We are uncertain if the intervention may influence infant long-term development at two years of age (2 studies with 69 infants).
• We are uncertain about the possible effect of music therapy on parental state-trait anxiety (4 studies with 97 participants) and postnatal depression (2 studies with 67 infants).
• We are very uncertain about a possible effect on parental state anxiety (3 studies with 87 parents).
• We found no studies which reported harmful effects of music or voice.
What are the limitations of the evidence?
We are confident that music and voice do not reduce oxygen saturation during the intervention compared to standard care. We are confident in our results of the substantial beneficial effect on the heart rate in preterm infants after the intervention. There are not enough rigorous studies (many small studies with poor recording standards) to be certain about the results of all other outcomes that we assessed in the infants and their parents. There is further uncertainty about music delivery and for which duration and frequency music works best.
How up-to-date is this evidence?
The evidence is up-to-date to 12 November 2021.