Preterm Infant Brain Injuries More Likely, Study Reveals

A recent study published by the Radiological Society of North America (RSNA) reveals that babies born between 32 to 35 weeks have the highest risk of developing preterm infant brain injuries and developmental delays, most likely due to brain size and lack of brain function development.

The new study focused on moderate to late term (MLPT) premature babies who are born anywhere from 32 to 36 weeks, which makes up the majority of preterm births in the past few decades. Even though most premature infants are born during this time frame, studies typically focus on births that occur before 32 months, making the new study of the first large-scale research projects on MLPT infants.

Using magnetic resonance imaging (MRI), researchers studied 199 MLPT infants, along with 50 babies who were born after 38 weeks. The goal was to look for signs that determine why and how brain injuries occured between the two groups. The lead author of the study, Jennifer M. Walsh, M.B.B.Ch., B.A.O., M.R.C.P.I., states that babies born prior to 32 weeks may have reduced oxygen and blood flow, which can lead to brain injuries. However, it’s not as easy to determine why preterm infant brain injuries are more likely. 

“In those very preterm babies, brain injury from bleeding into the brain or a lack of blood flow, oxygen or nutrition to the brain may explain some of the abnormal brain development that occurs. However, in some preterm babies, there may be no obvious explanation for why their brain development appears slow compared with babies born on time,” Dr. Walsh said. 

In addition, although both groups of infants had the same brain injury rates, the MLPT group had less myeline matter on one side of the brain and half-grown gyral folding. As a result, researchers believe that infants born between 32 to 36 weeks may have stunted brain growth during the crucial time period of infant develop during the last two months of pregnancy, which may lead to injuries and developmental delays.

“Given that brain growth is very rapid in the last one-third of pregnancy, it is perhaps not surprising that being born during this potentially vulnerable period may disrupt brain development. Brain growth is very complex, involving not only the neurons with which we think and do things, but also the other brain cells that support the neurons and are vital for normal brain function,” Dr. Walsh stated. 

As the research continues, experts hope to not only better understand MLPT injuries, but to establish the best forms of treatment, which may include early intervention and medication. Several treatment options may need to be tested before determining which ones provide the best outcome.

The infants studied in the research will be followed and observed throughout childhood and adolescence. Additional MRI procedures will be conducted periodically to figure out the function and brain structure of the MLPT babies. Per Dr. Walsh, although progress has been made as to what pre-term age group exhibits higher risks of brain injuries, more research is needed to understand why preterm infant brain injuries are more common. After the cause is determined, improving the infants’ long-term outcome will follow.