Premature babies can often be vulnerable
Even very premature babies benefit from skin to skin contact with their parents, research suggests.
A Canadian study found that cuddling babies born as early as 28 weeks reduced the stress of painful medical procedures which many must undergo.
Writing in the journal BMC Pediatrics, the McGill University team said it might aid the recovery process.
UK neonatal units do not always encourage skin to skin contact, said a London-based expert studying the issue.
There is already some evidence that regular cuddling can help babies, even those dependent on incubators, not only by promoting their health, but by encouraging a parental bond which could be important to their progress in months to come.
This study is the first to look at extremely premature babies, born between 28 and 31 weeks.
It was previously thought by some experts that such young babies were not developed enough to benefit from human touch.
A common test used in neonatal units is the "heel prick" blood test, which produces a sample which can be used to check blood sugar levels.
This is inevitably painful for the baby, and in some cases, it can take minutes for this distress to recede - which could be a problem for a baby whose health is in the balance.
The McGill researchers carried out the test on some babies who were being actively cuddled, skin to skin, measuring facial expressions, heart rate and blood oxygen levels to assess the amount of pain suffered.
Pain scores after 90 seconds for the cuddled babies were much lower than for those who were not cuddled.
Half the cuddled babies did not show any facial expression of pain when undergoing a heel prick test.
Lead researcher Celeste Johnston said that the shorter recovery time could help maintain the baby's health.
"The pain response in very preterm neonates appears to be reduced by skin-to-skin maternal contact," she said.
Professor Linda Franck, from the Institute of Child Health in London, said that parents were often not encouraged to have skin to skin contact with their premature babies in UK neonatal units, despite growing evidence that it could help.
She said: "Neonatal units can be very intimidating places, and parents often do not know the best way to get involved.
"Parents want to do the right thing, but the message is difficult to get out there.
"This study suggests that, even for the very youngest premature babies, skin to skin contact can reduce the stress response."
She is currently carrying out a pilot study in four London units which is using a variety of methods, including skin to skin contact, to encourage parents to become more involved with the care of their newborn children.