Babies who weigh very little at birth, usually born significantly before their due date, are surviving infancy more often than they used to, and doctors are beginning to pay more attention to how they develop as they get older. These babies are more susceptible to a host of complications including infections because their bodies are not yet fully grown. Researchers from all over the country conducted a study of more than 6,000 infants to see if infections in infancy stunted their development later in life.

What the researchers wanted to know: Do infections just after birth cause problems for low-birth-weight babies later in life?

What they did: The researchers examined more than 6,000 babies who weighed less than 2.2 pounds at birth and kept track of how many got an infection, such as sepsis or meningitis, right after they were born and were still in the hospital. They followed up when the babies were between 18 and 22 months old and interviewed each baby's mother, tested the baby's mental abilities, examined the baby's vision and hearing, and took vital statistics.

What they found: Children who had gotten an infection as infants were more likely to have developmental problems later in life than those who hadn't, including severe problems like vision deterioration and cerebral palsy. Overall, 65 percent of the low-birth-weight babies came down with an infection shortly after they were born, and 43 percent of the infected infants had neurodevelopmental problems. By contrast, 29 percent of the babies who did not have infections developed neurodevelopmental problems.

What it means to you: Parents of premature babies can face many challenges, including the babies' risk of neurological problems. As an accompanying editorial suggests, one of the ways to reduce the risk of these problems might be to watch for and aggressively treat infections in preemies. Infections that attack the central nervous system, such as meningitis, seemed to affect babies the most, probably because they interfere with neurological development.

Caveats: The researchers followed up with the babies only once after they left the hospital, so developmental problems may have worked themselves out over time or new problems may have developed that the researchers didn't catch.

Find out more: The Neonatal Research Network, which sponsored this study, has an information page for families with low-birth-weight babies. Another good site is found on the University of Wisconsin's Department of Pediatrics Web page; click on the topics on the left side of the page for more information,

Read the article: Stoll, B. J., et al. "Neurodevelopmental and Growth Impairment Among Extremely Low-Birth-Weight Infants With Neonatal Infection." Journal of the American Medical Association. Nov. 17, 2004, Vol. 292, No. 19, pp. 2357–2365.

Editorial: Msall, M.& E. "Developmental Vulnerability and Resilience in Extremely Preterm Infants." Journal of the American Medical Association. Nov. 17, 2004, Vol. 292, No. 19, pp. 2399–2401.

Abstract online: http://jama.ama-assn.org/cgi/content/abstract/292/19/2357

Editorial extract online: http://jama.ama-assn.org/cgi/content/extract/292/19/2399