NEW YORK — For preemies, the combination of hearing mother’s voice softly singing while being held against her skin can have a number of health benefits — and it helps moms, too, a new study suggests.
When mothers in a neonatal intensive care unit sang while holding their preterm infants in a skin-to-skin “kangaroo care” position, the babies’ heart rate improved compared to when they were held without singing. Mothers’ anxiety levels dropped as well.
“We noticed that many mothers want to speak or sing during kangaroo care as a natural feeling of love and care for their child,” said lead author Shmuel Arnon, a physician at the Meir Medical Center in Kfar Saba, Israel.
“I thought that singing in public will cause mothers who are not very musically talented to be embarrassed, but on the contrary they felt much more united with their child,” Arnon told Reuters Health.
“Holding a premature baby for the first time can cause a mother anxiety for a variety of reasons. The baby has tubes and lines that a mother might worry about messing up, and the baby is fragile, sometimes weighing less than a pound,” said Larry Gray, a pediatrician at Comer Children’s Hospital at the University of Chicago who was not involved in the new study.
Nevertheless, Gray said, skin-to-skin contact can be life-saving. The baby and mother become “in sync,” and in some cases the baby no longer has to work as hard to keep warm.
Every year, nearly 500,000 babies in the U. S are born prematurely, according to the Centers for Disease Control and Prevention. Beyond their tiny size, preemies are vulnerable to a number of health problems because their organs and nervous systems are not fully developed.
Past research has found that preemies’ breathing, heart function and feeding all improve when they hear mother’s voice, which is familiar from their time in the womb, Arnon and his coauthors write in Acta Paediatrica.
Other studies have found that kangaroo care can aid brain development, provide pain relief and help a preemie stay warm. The researchers write that both interventions are easy to implement and, at no extra cost, can be combined as a helpful distraction for anxious mothers.
To see whether adding singing to kangaroo care benefited babies or mothers, the study team recruited 86 pairs of mothers and infants between October 2011 and March 2012.
All the babies were born between four and eight weeks early, but were stable enough to participate and able to hear.
Over the course of two days, mother-infant pairs had kangaroo-care sessions with and without singing. Each therapy session started 30 minutes after the babies were fed. Mothers sat in chairs reclined at a 40-degree angle, holding their baby, who was clad only in a diaper, against their skin. A blanket was placed over the baby’s back and then the mother’s hospital gown was wrapped around the infant.
The sessions took place in a quiet room, and the babies’ heart rate, breathing and temperature were monitored.
On the day mothers were asked to sing, they were instructed to stick with a simple and repetitive lullaby in their native language, ideally one they had sung to the baby during pregnancy.
For the first and last ten minutes of each session, every baby received kangaroo care alone, but for 20 minutes in between, mothers assigned to the singing group were told to sing softly. The mothers could see a sound analyzer while they sang and were told to keep the volume of their singing between 60 and 70 decibels.
“We provided each mother a place for her to feel comfortable. Many mothers felt that it was easier to sing than to sit in KC [kangaroo care] position and do nothing,” Arnon said.
Before and after each session, mothers answered a standard questionnaire to measure their anxiety on a scale from 20 to 80, with 80 being the worst. Mothers were compared to themselves on days when they sang or didn’t sing, and the researchers found singing made a significant difference in their anxiety levels.
On average, mothers who didn’t sing during kangaroo care dropped from about a 56 on the anxiety scale before the session to a 43 afterward. Mothers who sang dropped from a score of about 51 beforehand to a 26 after.
For the babies, researchers were interested in changes to the infant’s heart rate variability, a measure of nervous system strength and health that’s based on the number of heart beats during breathing in and out.
They found the infants’ heart rate measurements were significantly better during kangaroo care with singing compared to kangaroo care alone, and they were also much better during and after the singing sessions compared to the period before the mother started singing.
“Even preterm infants recognize their mother’s voice from the womb. By using kangaroo care to deliver music, the baby enjoys other stimuli such as vibrations, smell, tactile, auditory and warmth,” Arnon said.
Gray called the study “fabulous” and said it shows that skin-to skin contact can help both the mother and the baby. It also “shows that babies do best when mothers are allowed to be mothers,” he noted.
“We live in a wonderful world where we have high powered technology that saves lives. Babies need their mothers just as much as they need this medical technology and this study shows that they can get both,” Gray said.