Babies born at a very low birth weight are more likely to have memory and attention problems when they become adults than babies born at a low to normal weight, according to a study published in the December 6, 2011, print issue of Neurology, the medical journal of the American Academy of Neurology.
"While we know babies born severely preterm generally achieve lower cognitive test scores, this is one of the first studies to look at how severely low birth weight impacts executive functioning, such as attention and visual memory, when these babies become young adults," said study author professor Katri Räikkönen, PhD, of the University of Helsinki in Finland.
For the Helsinki Study of Very Low Birth Weight Adults, 103 adults born with a very low birth weight (less than 3.3 pounds) and 105 adults who weighed more than 3.3 pounds at the time of birth were given tests that measured their thinking skills, including vocabulary, ability to understand words, memory and IQ. Participants were between the ages of 21 and 30.
The study found that adults with very low birth weight scored lower or performed slower in general intelligence, executive functioning and attention and visual memory compared to the adults born at a low to normal weight. For example, those with a very low birth weight scored an average 8.4 points (0.57 standard deviation units) lower on the full IQ test and 0.30-0.54 standard deviation units lower on the executive functioning and attention and memory tests.
Researchers also found those with very low birth weight were more likely to have received remedial education while in school, but there were no differences in their self-reported academic performance.
"Interestingly, average school grades and the number of years of education completed were not affected by low birth weight in our study," said Räikkönen. "However, our research underscores the importance of a baby's full development in the womb."