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
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
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
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
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.
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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,”
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.
Acta Paediatrica, online August 11, 2014.
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