Littlest Babies Damaged by Infection

November 17, 2004 -- Extremely low birth weight infants are at high risk for developmental impairments if they have an infection during the newborn period, according to a new report appearing today in the Journal of the American Medical Association.

The extremely low birth weight infants in this study weighed 1000 g (2.2 lbs) or less. The developmental impairments they tended to suffer following infection included cerebral palsy and diminished intelligence as well as decreased physical growth.

Our Comments

Neonatal infections are frequent problems for extremely low birth weight infants who must receive intensive care if they are to survive. The infections may be almost anywhere, it appears. Not just meningitis but also sepsis (bloodstream infection) and necrotizing enterocolitis (an intestinal infection) can impair the baby's development.

There is a need for increased excellence in preventing infection in these very vulnerable babies. We are doing better in saving their lives. We must do better in protecting them from lasting disabilities.

Barbara K. Hecht, Ph.D.
Frederick Hecht, M.D.
Medical Editors,

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Infection Puts Extremely Low Birth Weight Infants at Risk For Developmental Delays

Extremely low birth weight infants - the tiniest category of premature infants - are much more likely to experience developmental impairments if they acquire an infection during the newborn period, according to a study by the Neonatal Research Network of the National Institute of Child Health and Human Development, one of the National Institutes of Health. The developmental impairments were seen regardless of the type of infection - whether it occurred in the brain, blood or intestines.

The study was conducted by Barbara J. Stoll, M.D., of the Emory University School of Medicine in Atlanta, Georgia and her colleague. Appearing in the November 17 Journal of the American Medical Association, the study reported that 65 percent of a group of extremely low birth weight infants had developed at least one infection during their hospitalizations after birth. These infants were more likely to have an impairment than were infants who had not developed an infection.

"This study shows us that successfully treating an extremely low birth weight infant's infection does not automatically ensure that the infant will do well," said NICHD Director Duane Alexander, M.D. "Parents and health care workers need to monitor these children carefully as they grow, and be ready to provide them with developmental and educational services, if necessary."

According to the U.S. Centers for Disease Control and Prevention, there were 60,326 very low birth weight infants born in 2002, or 1.46 percent of the 4,021,726 total births for that year. Infants are classified as low birth weight if they are born weighing less than 2500 grams (about 5.5 pounds) and very low birth weight if they weigh less than1500 grams (about3.3 pounds). In the current study, the researchers analyzed the records of extremely low birth weight (ELBW) infants - those weighing less than 1000grams, or 2.2 pounds. Yearly statistics are not compiled on ELBW infants. Study co-author Rosemary Higgins, M.D., of NICHD's Pregnancy and Perinatology Branch, estimated that as many as 50 percent of newborns below 1500 grams may fall into the ELBW category.

The study enrolled infants weighing from 401 to 1000 grams at birth. In all, 6,093 infants were evaluated for this study. The infants were evaluated when they were between 18 and 22 months corrected gestational age - equivalent to the age they would be had they been born at term. The researchers found that the majority of these infants (65 percent) had at least one infection during their stay in the hospital after birth.