Premature babies should be breastfed to ensure their brains develop properly, a new Scottish study found.

Babies born before 33 weeks had better improved brain structure and connections if fed breast milk compared to those given formula.

Premature babies are more at risk of having problems with learning and thinking skills in later life, which are thought to be linked to alterations in brain development.

Studies showed pre-term birth was associated with changes in the part of the brain's structure that helps brain cells to communicate with one another, known as white matter.

But helping mothers to provide breast milk in the weeks after giving premature birth could improve long-term outcomes for their children.

About eight out of 100 babies will be born prematurely before the 37th week in the UK.

Professor James Boardman, Director of the Jennifer Brown Research Laboratory at the University of Edinburgh, explained: "Preterm birth is strongly associated with a magnetic resonance imaging (MRI) phenotype that includes altered structural connectivity of developing neural systems involving white matter, structural alteration in deep and cortical grey matter, and long term neurocognitive impairment.

"Nutritional factors may play an important role in preterm brain development.

"For example, optimal protein and energy intakes in the first days after preterm birth are associated with increased brain growth, improved white matter microstructure and neurodevelopmental performance.

"Breastfeeding, when compared with formula feeding, is associated with increased performance in intelligence testing among the general population, and the effect may be enhanced in low birthweight infants."

So researchers at the University of Edinburgh studied MRI brain scans from 47 babies from a study group known as the Theirworld Edinburgh Birth Cohort.

The babies are part of a longitudinal study designed to investigate the effects of preterm birth on brain structure and outcome The babies had been born before 33 weeks gestation and cared for at the Royal Infirmary of Edinburgh.

They had brain scans when they reached term-equivalent age, an average of 40 weeks from conception.

The team also collected information about how the infants had been fed while in intensive care - either formula milk or breast milk from either the mother or a donor.

Babies who exclusively received breast milk for at least three-quarters of the days they spent in hospital showed improved brain connectivity compared with others.

The effects were greatest in babies who were fed breast milk for a greater proportion of their time spent in intensive care.

Professor Boardman said: "Our findings suggest that brain development in the weeks after preterm birth is improved in babies who receive greater amounts of breast milk.

"This study highlights the need for more research to understand the role of early life nutrition for improving long-term outcomes for pre-term babies.

"Mothers of pre-term babies should be supported to provide breast milk while their baby is in neonatal care - if they are able to and if their baby is well enough to receive milk - because this may give their children the best chance of healthy brain development."

The study was funded by the charity Theirworld and its president and trustee Sarah Brown said: "This latest report delivers valuable evidence to support breast milk feeding for even the tiniest, most vulnerable premature babies, to give them the best start in life.

"An immense debt of gratitude is due to the families of the Theirworld Edinburgh Birth Cohort, who are dedicated to sharing information to support their own little ones, and benefit many other premature babies in the future."

The study was published in the journal NeuroImage.