Many ‘Preemies’ Don’t Outgrow Cognitive, Other Problems

It garnered front-page headlines from the New York Times to the Cleveland Plain Dealer. And depending on where it appeared, the story about research on long-term outcome of prematurely born babies could be read in variable light: either as encouraging evidence that they do better than expected, or as a sobering reminder that the developmental problems experienced by “preemies” persist into adulthood.

In fact, the study—which appeared in the January 17 edition of the New England Journal of Medicine—suggests both.

Led by Maureen Hack, M.B., of the department of pediatrics at Case Western Reserve University School of Medicine and the University Hospitals of Cleveland, the study compared 242 survivors among low-birth-weight babies born between 1977 and 1979 with 233 controls with normal birth weights from the same population in Cleveland.

On the sobering side, the study found that fewer individuals in the preemie group had graduated from high school and that they had lower academic achievement, higher rates of neurosensory impairments, and subnormal height. Very-low-birth-weight individuals had significantly lower mean IQ scores than controls (87 versus 92), and had a higher frequency of subnormal IQ (defined as lower than 70) and borderline IQ (70 to 84). Fifty-one percent of the very-low-birth-weight individuals had an IQ in the normal range (equal to or greater than 85), compared with 67 percent of the controls. These differences remained significant when the comparisons were restricted to participants without neurosensory impairment, the researchers stated.

On the encouraging side, the study found that the preemie group reported less alcohol and drug use, had less contact with the police, and had lower rates of sexual activity and pregnancy at 20 years of age.

Psychiatrists who addressed the study’s implications for behavioral and mental health tended to emphasize the hopeful message in the findings, while underscoring their preliminary nature.

“When you see these kids very young, you tend to wonder what the course of their life will be like,” said Marilyn Benoit, M.D., president of the American Academy of Child and Adolescent Psychiatry and program director for child psychiatric services at Howard University Hospital in Washington, D.C. “But the core message from this study is a sense of hope.”

The finding that developmental delays persist into adulthood is “not at all surprising,” Benoit told Psychiatric News. “What was unexpected is their relative success despite their difficulties. When recognized early and treated with appropriate and sustained interventions that involve the parent, these kids can have a very decent life.”

Noting the relatively poor performance of controls as well—and the fact that the study population was drawn from a lower socioeconomic cohort in Cleveland—Benoit also emphasized the potent effect of poverty on outcome for all children.

“The good news we can tell parents is that there are many children who are born at very low birth weight who appear to do quite well,” said David Fassler, M.D., chair of APA’s Council on Children, Adolescents, and Their Families. “That is an important and encouraging message. Now we need to figure out which kids are at relatively greater risk and find interventions that are effective for those children.”

But Fassler, noting the varying treatments the study received in the popular press, suggested it might reveal as much about the variations in spin to which research may be subject when a difficult study about a challenging subject of wide public interest turns up differing findings.

Fassler said the relatively small sample size and improvements in neonatal care since the time when the preemies in the study were born make it difficult to draw firm conclusions one way or the other.

“It raises a lot of interesting questions, but we should consider the findings preliminary,” he said. “The study is interesting and useful, but it is not yet specific enough for us to make clinical predictions for a particular child.”

Fassler noted that of an initial cohort of 490 babies with very low birth weight (those weighing less than 1500 grams), only 316 (64 percent) survived to the second year. An additional four children died before age 20, and 70 were not studied for a variety of reasons.

“We need to be careful that we are not looking at a somewhat skewed sample,” said Fassler. “In the next phase of their research, the authors will look at specific parameters to help parents and physicians use this information in a more meaningful way. For example, is the outcome different based on the level of the child’s impairment?”

In an interview with Psychiatric News, lead researcher Hack said that in subsequent research using the same population, she hopes to employ in-depth psychiatric interviews to answer more fully questions about behavioral and mental health, as well as overall functioning.

Of importance to psychiatrists, Hack said the NEJM report did hint at higher rates of bipolar disorder among the preemies (2 percent) than among controls (1 percent). In addition, Hack said there is evidence in the medical literature to suggest that the presentation of attention-deficit/hyperactivity disorder may differ among preemies—an hypothesis that subsequent research will also explore. She said it is possible that preemies who develop ADHD have a more marked presentation of attention problems but less hyperactivity.

For now, she highlighted the study’s positive findings. “Overall the children are functioning fairly well,” she said. “It is true that there is lower IQ and less educational achievement, especially among males, but the subjects are functioning.”

Hack noted that the study also looked at rates of employment and found them to be similar among both preemies and controls.

One of the more intriguing hypotheses to emerge from the study is the idea that the relatively good outcome of preemies overall—and particularly their lower rates of risk-taking behavior—may be due to family resilience and increased paternal monitoring of children.

The idea was addressed in an editorial accompanying the study by Marie McCormick, M.D., Sc.D., of the Harvard School of Public Health.

“Clues to the nature of this resilience may be found in studies demonstrating that although very-low-birth-weight children accurately characterize themselves as having more health-related and learning difficulties than their normal-birth-weight peers, their ratings of their health-related quality of life are higher than those of their peers,” McCormick wrote in her editorial.

Fassler agreed that the hypothesis is worthy of more research, but said it remains speculative. “Another hypothesis is that these are kids who have more contact with the health care system,” he said. ▪