Brain scans of preterm babies in new study

The world-first study will be led by Distinguished Professor Jane Harding at the University of Auckland-based Liggins Institute in collaboration with Professor Steve Miller from the renowned Hospital for Sick Children in Toronto, Canada. It will run at Auckland City, North Shore, Waitakere and Middlemore hospitals.

Researchers will take MRI scans of preterm babies’ brains a few days after birth, and then again at their due date, to see how nutrition in the first days, while the babies are still learning how to breastfeed, affects brain growth and development.

Today, the researchers received $1.2 million in funding from the Health Research Council (HRC) to begin the study, which will involve 96 babies born at 32-36 weeks’ gestation.

Professor Harding: “We hope this study will allow us to identify ways of feeding these babies that will enhance their brain development. It’s exciting not only because this is the first time anyone has looked at the effect of nutrition on brain growth and development in moderate-to-late preterm babies, but also because it will help us develop new techniques in collaboration with world experts.”

For the MRI scans, the researchers will use a technique pioneered in Toronto. “We feed the babies, tuck them up in a special incubator that is compatible with the MRI scanner, and wait for them to go sleep, so they keep still during the scan. Then we slide the whole incubator into the MRI machine so the baby is not disturbed.”

The scan takes 30-40 minutes – cut short if the baby wakes up – and is completely safe. Professor Harding: “MRI has been used for many years as a routine assessment of even the tiniest preterm babies in many hospitals overseas. It is non-invasive, involves no radiation and has no known side effects.”

Every year, around 5000 babies are born preterm in Aotearoa New Zealand. The vast majority survive, but they carry a greater risk of problems with growth, learning, and adult diseases such as obesity and diabetes than babies born at term.

The new study builds on the Liggins Institute-led DIAMOND study, which is comparing different ways of providing nutritional support to preterm babies learning how to breastfeed. Researchers believe that optimising how and what preterm babies are fed in those critical first days or weeks could prevent diseases later in life and help intellectual development.

“Nutrition offers the simplest and least expensive way of improving the long-term health for these babies,” says DIAMOND study lead Professor Frank Bloomfield, Director of the Institute. “It's the first step towards personalised medicine for preterm babies.”

Preterm babies face many difficulties with feeding. It can take days before their mothers start producing enough breast milk, and up to weeks before the baby’s gut is mature enough to tolerate the milk. For preterm babies born at 32-36 weeks, there is almost no evidence to guide doctors on how best to feed babies in this period, and practice varies widely. One common approach is to give babies a sugar solution intravenously (into their veins) while gradually increasing the amount of milk fed via a nasogastric tube down the nose into the stomach, finally shifting to breastfeeds when the baby is ready.

The main DIAMOND study has been running for 18 months. Babies are randomly allocated to receive intravenously just sugar water or sugar water plus protein. They also either receive a specially formulated human milk substitute via the feeding tube while waiting for mother’s breast milk supply to build up, or just wait until the breast milk is available. On top of this, half are helped to smell and taste a few drops of milk before the tube-feed, as evidence from a pilot study suggests this may help them feed earlier.

Researchers in the new brain MRI study have proposed that giving babies protein-boosted sugar water intravenously may affect how the cerebral cortex – responsible for high level brain functions – matures. They also propose that breastmilk may support developing connections between nerve cells, and that exposure to the smell and taste of milk before a tube-feed may alter maturation of the thalamus – an important co-ordinating centre at the base of the brain.

Professor Harding: “Better early brain growth and maturation is associated with better development as the babies get older. If we can pinpoint the feeding approach that best supports early brain development, we may significantly lower the risks of these babies experiencing learning difficulties later in life.”