Breastfeeding will help premature babies’ brains develop normally, a new study found.
A baby's brain and other organs complete their development during the final months and weeks of pregnancy.
So those born before full term are at greater risk of developmental problems in later life because their brains have not fully developed.
About one baby in every 13 will be born before the 37th week of pregnancy.
The NHS recommends breast feeding to boost good bacteria in their stomachs to fight off infection while hormones and growth factors in the milk helps the baby grow and become stronger.
Now a new study by Washington University School of Medicine in St. Louis suggested breast milk may help promote brain development in premature babies and protect them from neurologic disorders as they grow up.
Feeding premature babies at least half of their daily fluid intake from breast milk in the first month ensured the infant had similar brains to those born at the right time.
The study followed 77 premature babies born in the St. Louis Children's Hospital Neonatal Intensive Care Unit.
They had brain scans while sleeping or resting at about the time they would have been born had they not arrived early.
These images were used to evaluate both the brain volume and the surface area of the cortex of their brains.
Results showed the more days a baby was breastfed in the month after its birth the more total brain tissue volume and cortical surface area they had near the time of their full-term date.
Assistant Professor of child psychiatry Dr Cynthia Rogers said: "Changes in brain volume and cortical surface area may be related to intelligence, attention or emotional regulation later in life.
"So we would hypothesise that the larger volumes and cortical surface areas we observed may suggest better developmental outcomes later in life"
She added being born prematurely also has been linked to psychiatric disorders later in childhood but breastfeeding could protect against these conditions.
Prof Rogers said: "We will need to continue studying these children, though, to understand whether the effects of breast milk on the brain really have an impact on cognitive function as the very preterm children grow up."
The study will be presented at the Pediatric Academic Societies 2016 Meeting in Baltimore.