The study examined the deaths of 137 babies

Of the 137 babies who died during a two-year period, the majority had brain damage which occurred during pregnancy, according to researchers.

But the study failed to identify anything in the mothers, or during the pregnancy and labour, which could have predicted problems with the babies.

The findings have been hailed as an important breakthrough.

The research, which involved paediatricians, obstetricians and pathologists from across the country, was led by Professor Neil McIntosh of Edinburgh University.

He said: "This study shows that in 36% of babies born early and in 61% of those born at term, there is evidence of significant brain damage that had clearly happened before labour began.

"This is far more common in infants born in an asphyxiated or suffocated condition."

It's important for the parents to know they have done nothing wrong, but it's also important for staff to know that too Prof McIntosh

The study included detailed examinations on the brains of about two-thirds of the 137 babies involved.

Professor McIntosh said the research showed that all the full-term infants who had symptoms of asphyxiation and who then went on to have brain problems had evidence of pre-existing damage.

More than half the premature babies born with features of asphyxia also had evidence of earlier damage.

Professor McIntosh, who is also a neonatal consultant with NHS Lothian University Hospitals Division, said the findings would reassure parents and medical staff who often felt guilt following the death of a new baby.

"It means that mothers haven't delayed in coming in with any potential problems and cannot feel guilty, and it means the staff haven't messed it up," he said.

"It's important for the parents to know they have done nothing wrong, but it's also important for the staff to know that too."

'Reassuring findings'

He said the findings could also reduce legal actions taken against doctors and midwives for perceived mismanagement of pregnancy and labour.

During the study parents were asked to complete "highly detailed" questionnaires giving information on a wide range of aspects of their lives, background and pregnancy.

Professor McIntosh said: "We couldn't find anything in the questionnaire that would lead us to predict the baby would be damaged.

"It is reassuring that nothing has been identified that says parents are being silly or staff are mismanaging things."

Professor McIntosh said more tests needed to be developed in order to spot potential problems earlier in the pregnancy.

"In about 10% of cases of a baby being born asphyxiated there's a reason, but in 90% there's not.

"We intend that this study will lead to more research into the monitoring of pregnancies."

The study was funded by the Chief Scientist Office and by the reproductive health charity WellBeing.

Shirley Farmer, director of WellBeing, welcomed the findings.