Music played to premature babies may lessen their pain and improve their feeding habits, a new study said.

Researchers from the University of Alberta took a look at nine previous studies -- all randomized trials, one of the most reliable forms of experiment -- to see if music could improve babies' breathing, lead to faster weight gain or shorten hospital stays.

The studies often used measurements such as heart rate, breathing and signs of pain to judge if music helped the babies.

One of the high quality studies looked at using music during circumcision. It showed music did have benefits for infants' heart rate, oxygen saturation and pain tolerance, according to a news release.

In three of the studies that looked at heel prick -- a common procedure for taking a blood sample from newborns -- there was evidence that using music could have benefits.

"There is preliminary evidence to suggest that music may have beneficial effects in terms of physiological parameters, behavioral states and pain reduction during painful medical procedures," the authors of the review said. "While there is preliminary evidence for some therapeutic benefits of music for specific indications, these benefits need to be confirmed in well-designed, high quality trials."

The study will appear in the Archives of Disease in Childhood.