Brahms's Lullaby might be good for much more than a heavy-eyed baby.
Music played to premature infants may help lessen their pain and ease the transition to bottle feeding, according to a new review study by Canadian researchers.
The findings, published in the Archives of Disease in Childhood, suggest that the trend of bathing babies in music is paying off.
Increasingly, neonatal units around the world are playing lullabies and sounds that mimic those that fetuses hear in the womb, hoping the music will improve the babies' behavioural and physiological outcomes, and alleviate pain during circumcision and other common procedures.
The benefits are said to include calmer infants (and parents), a stable condition in the child's functions, higher oxygen saturation, faster weight gain and shorter hospital stays. Popular preemie music includes recorded versions of Brahms's Lullaby and Hush-a-bye Baby.
Some of the studies combined lullabies with what the fetus would hear in utero, sounds such as heartbeats and blood flow, said Manoj Kumar, an assistant clinical professor at the neonatal division in the department of pediatrics at the University of Alberta.
He and other researchers at the university reviewed nine random trials, many of them American, published between 1989 and 2006, to evaluate the value of music in neonatal wards. Three studies looked at the impact of music played during circumcisions, and found decreased overall pain and benefits to the infants' heart rates and oxygen saturation.
"Usually, when you have a painful response, the heart rate would go up and the oxygen saturations can drop. Those were the parameters that seemed to get more stable when the music was [playing]" Dr. Kumar said.
Three other studies focused on heel pricks, a common blood sample taken from newborns' heels. Here, evidence suggested the music also helped assuage pain.
Another study looked at feeding rates: Researchers found that playing music while babies sucked on pacifiers helped ease the transition from gavage feeding (via nasal or oral gastric tubes) to bottle feeding, which benefits both the child and the stressed health-care system.
"This was called the pacifier-activated lullaby system. What they noticed was that the babies subjected to the system had better feeding rates than the ones not subjected to the system," Dr. Kumar said. "If they're feeding faster, maybe we could get them out of the hospital faster. If you could get a baby out of the hospital even a day earlier, that's a huge cost saving."
Many of the studies the researchers reviewed were small, and Dr. Kumar is calling for larger-scale trials on the topic. Asked whether the lullabies could inadvertently trigger a Pavlov's dog-type response, with adults conjuring pacifiers with every Sandman rendition, or worse yet, boys recalling their circumcisions every time Brahms's Lullaby strikes up, Dr. Kumar remained unruffled.
"If you look at it from that perspective, it would only be better," he said. "There is some literature on having long-term memories of painful responses. If pain is reduced through these procedures, then it can only have a beneficial effect in those terms, too."