Yale-New Haven was recognized this year by U.S. News & World Report for its pediatric services.

Preemies improve over time

In the 1980s, only about one-third of very small premature newborns survived. These days, the percentage has doubled to about 63 percent, or about 25,000 children per year. Given the likelihood of developmental difficulties in these children, it's in everyone's best interest to track their progress over time.

When we began the prevention trial, we had always planned to follow these children for several years. But even before the results were in, one mother kept saying to me that she had noticed her triplets were getting smarter as they got older. When we saw the data, it proved her right. We were genuinely thrilled.

The findings were surprising because previous research has found long-term consequences in very small preemies and conventional wisdom says that IQ does not change.

More than two thirds of children who had borderline intelligence scores at age three had test scores in the normal range (above 70) by age eight. By eight years of age, the children in the study increased their Peabody Picture Vocabulary IQ score by 11 points from 88 to 99. A score of 100 is considered average for normal birthweight eight-year-olds.

This suggests that the premature brain is able to repair itself over time, which is a fascinating concept. Our study is the first clinical evidence recognizing this, but there is still so much we don't know. Recent research in animals has shown that a developing brain can repair itself.

The societal implications of a five-point difference in IQ are large. A score below 70 mandates special education in many school districts. Special education is not only costly but carries a certain stigma.

Research takes years
One difficulty in doing this type of research is that it takes years to complete. These children were all born in the late 1980s or early 1990s. At that time, we were dependent on using a cranial ultrasound to detect brain injury. There are better ways now to do so and better ways to manage premature infants.

Another limitation is that we picked environmental and genetic factors to investigate. There may be other factors out there that influence development, such as medications the infants receive, the use of ventilators or the mode of delivery (c-section vs. vaginal delivery).

Beginning at birth
One strength was that the children were enrolled within six hours of birth and we followed them for eight years. We could assess from the beginning what was going on with them, whether they had an intraventricular hemorrhage (IVH), and if so, whether that had an effect long-term. All the children were assessed with the same tests at the same ages and we tested everyone and continue to test them.

The next step is to replicate the study and to use magnetic resonance imaging (MRI) to analyze the brain volume of these children. A previous study we did showed that the children's brains at age eight were smaller than brains of normal birthweight eight-year-olds. We will look at the brain volume at age 12 to determine if the brain differences remain the same or decrease over time.

We appreciate the cooperation we have received from the families over the years. They know they are helping to provide information that will help premature infants in the future.

Dr. Ment is an attending pediatrician at Yale-New Haven Children's Hospital and a professor of pediatrics and neurology at Yale University School of Medicine.