Babies Born Very Small Are Likely to Have Problems Later
June 22, 2000 -- Premature babies who are very small at birth run an increased risk of developmental problems that can be detected as early as 18 months of age, according to a study in the journal Pediatrics. Experts believe these problems will become more common as medical advances allow the survival of infants born more than three months premature and weighing 1 pound, or even less, at birth.
Study author Betty Vohr, MD, and her colleagues studied the conditions at 18-22 months of more than 1,100 extremely low birth-weight children (defined as babies weighing about 1 to 2 pounds at birth) delivered at 12 hospitals around the U.S. in 1993 and 1994. They evaluated the babies' development, mental functions, and medical and social histories. According to Vohr, the tiniest baby weighed only 14 ounces at birth.
In an interview with WebMD, Vohr stresses that the children's scores in these areas were evaluated on an age-adjusted basis. For example, she says, "a child born at 28 weeks might have a chronological age of 6 months, but a developmental age of only 3 months." This is important because, in such a child, certain developmental milestones can continue to occur after birth -- just as if the baby had remained in the womb those remaining three months.
Overall, development was normal in over half of these children by age 18 to 22 months. Seventeen percent of the children had cerebral palsy, 11% had some form of hearing impairment, and 9% had vision problems. The lower a child's birth weight was, the greater the risk of visual impairment or neurological problems.
Children who had steroid therapy for chronic lung disease immediately after birth seemed to have the most severe problems, perhaps because they were the sickest infants. It's not known how steroids may have produced this effect, but the researchers point out that steroids may have a toxic effect on the brain. Vohr tells WebMD that the use of neonatal steroids is now being re-evaluated.
The researchers also point out that having a higher socioeconomic status may blunt some of the worst effects of being born so early. Factors such as the mothers' education level and race were strongly associated with their children's scores on tests of mental development at 18-22 months of age.