Children who are deprived of even small amounts of blood or oxygen at birth can have lower IQ levels and increased rates of disability, according to a new study.

The study by the INFANT Centre, based at University College Cork followed a group of babies that suffered different levels of Hypoxic Ischaemic Encephalopathy or HIE until they were five.

HIE is a brain dysfunction caused by a reduction in the supply of oxygen to the brain and other organs, compounded by low blood flow to vital organs.

The team at INFANT, led by Dr Deirdre Murray, monitored the brain function in babies in the days straight after birth.

Follow-up research when the children reached the age of five found that the babies that had been admitted to the Neonatal Intensive Care Unit with mild HIE had an average IQ that was 10 points lower than their peers.

A third of those children also had higher than average rates of difficulty in one or more areas of development including learning, speech, movement or behaviour.

The researchers say the finding suggests that a therapy, which involves cooling the heads of babies with moderate or severe HIE at birth, could also help babies with mild HIE in the longer term.

At present all babies with a moderate or severe grade of HIE are offered cooling therapy, because it reduces the amount of energy expended by the brain, thereby reducing inflammation and giving the brain recovery time.

In babies with moderate and severe HIE, cooling therapy has proven to halve the risk of cerebral palsy or moderate-to-severe disability.

However, no research has yet been done on the use of cooling therapy in babies with mild HIE because it was thought to be unnecessary.

Around 180 children born every year in Ireland suffer from HIE.

The research, published in the journal Pediatrics, was funded by the Health Research Board.