Premature birth can be risky, to both mom and baby, but thanks to modern medicine, most preemies can be nurtured into a healthier and stronger state after a few weeks in neonatal intensive care. Still, even among babies who thrive, some developmental effects of being born too early may last into adulthood, new research finds.
In the first study to look at the long-term effects of prematurity on higher-order cognitive abilities such as memory and attention, researchers found that when tested in early adulthood, people who were born extremely premature — with a birth weight of less than 3.3 lbs. — generally scored lower on tests of executive function than babies born full-term. They also tended to take more time to complete these tasks. On IQ tests, adults who were born premature scored 8.4 points lower on average than those who were born full-term.
But as disappointing as the results sound, lead author Katri Rikkonen, professor of psychology at University of Helsinki, says that the future for premature babies isn’t necessarily bleak. Although the differences between preterm and full-term babies that she and her team found were statistically significant, on a practical level, the gap didn’t translate into any deficits in the way they lived their lives. (Also, with an average IQ of 102, those who were born preterm were still within normal IQ range.)
The two groups, comprising just over 200 people, finished their schooling in the same number of years, and the adults who had been born premature maintained similar grades to those born full-term. “The good part of this study is the findings show that after all, those born premature are not doing that worse at all,” Rikkonen says. “We can see differences, but they are doing fairly well overall.”
Why exactly does preterm birth cause cognitive changes? Most likely because of alterations in the way the babies’ brains developed, as well as minor but real brain injuries caused by leaving the womb too early. “Even though these brain injuries are not significant in terms of lowering IQ too much, there do seem to be minor injuries due to premature birth that can hinder brain plasticity and normal cognitive development,” says Raikkonen. While her study did not specifically look at brain images to verify this theory, other researchers have proposed and documented similar structural differences in the brains of prematurely born individuals.
The results should sound a warning for doctors and parents about the potentially long-lasting consequences of preterm birth, and help guide them to mitigate some of those effects. Breast-feeding, for instance, may be one way to promote some of the early brain development that doesn’t get a chance to occur in utero. At school age, supplemental help may also benefit these children. Although those born as preemies got the same grades and graduated at the same time as their full-term peers, premature children were more likely to have needed remedial classes in school to get there.
Raikkonen emphasizes that whatever deficits being born prematurely may have on the brain, some of these can be offset by such training or extra support. “If we know prematurity may carry some risk on proper cognitive development, it should be taken as a warning to pay attention,” she says. “We can then try to improve the environment and add techniques to enhance the cognitive development of these children as much as we can. Focusing on their cognitive development may diminish the differences between these groups when it comes to real life functioning.”
It’s a miracle when babies born too early can survive to become healthy and productive children and adults. It’s just a matter of helping the miracle along, all the way from intensive care, through infancy and into childhood. “Early intervention and prevention are really important in these cases,” says Raikkonen.