Parents want to play a greater role in caring for their newborn babies in intensive care, researchers have found.
Parents are often not told how to spot their baby is in pain
A joint US and UK study of 257 parents found 87% wanted to be able to do more to control their baby's pain.
The research, published in Archives of Disease in Childhood said a lack of information increased parents' stress at an already difficult time.
Experts said parents should be given more information about their baby's care.
The researchers surveyed parents whose babies were being cared for at nine neonatal intensive care units (NICUs) in the UK and two in the US.
They estimated levels of parental stress by asking them how bad they thought their baby's pain had been, how worried they were and how satisfied they were with the information they were given.
The researchers took into account how sick the child actually was, and how satisfied parents were with treatment overall.
It was found many parents were unclear about the treatment their child had received to reduce their pain.
Thirty per cent did not know if their baby had been given pain medication, while 15% thought their baby had been given the drugs, even though there was no record of the treatment in the baby's notes.
The researchers also found parents had little involvement in caring for their babies.
While 55% said they were shown how to comfort their child, only 18% were told how to spot if the baby was in pain
And although more than half said they had been told about how their child's pain was being managed, only 4% were given written information.
Professor Linda Franck, of the Institute of Child Health, who led the study, said: "Children's pain is now taken much more seriously than it was 10 years ago, but this study shows we still have some way to go to help parents prepare for and deal with the stress of having a sick child who requires painful treatments.
"We are currently seeking funding for a larger trial, which will test a new ways of giving information about infant pain and involving parents in their infant's care."
Professor Franck said parents had been generally happy with the attention doctors and nurses gave to infant pain care.
But she added: "The main message from mothers and fathers from all backgrounds is that they want to know as much as possible and do anything they can to comfort their baby."
A spokeswoman for the premature baby charity Bliss, told BBC News Online: "Many parents feel marginalised because they're not involved with their baby's care and seeing their baby in pain causes enormous distress.
"There is a role for parents when painful procedures are undertaken as they can be in a position to calm the baby.
"Parental inclusion is particularly important as feelings of helplessness and uselessness are frequently reported; the normal caring role is taken away from these mums and dads and this can result in high rates of anxiety, post natal depression and post traumatic stress."