Most Very Premature Babies Are Alive And Well At 4, Only 1 In 5 Experiences Serious Problems, Study Shows

BUFFALO, N.Y. -- University at Buffalo researchers following the health of 194 babies born 12-17 weeks prematurely have found that after four years, the majority of the children were alive and well and had no major neurodevelopmental impairments.

However, results showed that one-fifth of the survivors exhibited at least one of the serious problems associated with extreme prematurity -- mental retardation, cerebral palsy, blindness or deafness.

Babies at greatest risk of dying because of their very early births were more likely to be male, weigh less than 800 grams at birth, and to have not received calf-lung surfactant therapy to speed maturation of their lungs, according to the findings.

The study appears in the February issue of the Journal of Perinatology.

Michael E. Msall, M.D., UB associate professor of pediatrics and rehabilitation medicine, and lead author of the study, said most long-term studies of the effects of extreme prematurity were conducted before the introduction of surfactant therapy, and that research done during the surfactant era has focused almost exclusively on the first one-to-two years of life.

“Many more babies are surviving prematurity since the advent of surfactant therapy,” noted Msall, who is affiliated with the Robert Warner Rehabilitation Center of Children’s Hospital of Buffalo. “There is a need for follow-up of these survivors to obtain valid long-term outcome data.

"Our purpose was to identify the risk factors for mortality and major neurodevelopmental impairments before these children reach kindergarten age. Identifying risk factors could lead to interventions that could improve their long-term survival and enhance their quality of life.”

Msall’s team studied 194 infants born between 23 and 28 weeks of gestation at Children’s Hospital between 1983 and 1986. Their progress was monitored in the intensive-care nursery and later through a follow-up program of the Robert Warner Rehabilitation Center. Standard tests were administered at approximately 52 months of age to 149 of the 153 children who survived that long.

Results showed that 79 percent of the survivors had no major impairments. Of the 31 children showing serious impairments, 15 experienced mental retardation, seven had cerebral palsy, one was blind and eight had multiple conditions.

Having a bacterial infection (sepsis) as a newborn, or being male or non-white were the most significant risk factors for developing a serious impairment.

Msall said this study is the first to pinpoint sepsis as a risk factor for major neurodevelopmental impairments and for mental retardation in particular.

“Perhaps sepsis is a marker of infants who are sicker and require more invasive monitoring,” Msall said. “Mental retardation from sepsis may reflect the vulnerability of the developing brain to a systemic insult. ”

Analysis of specific impairments showed that hydrocephalus (excess fluid in the brain) requiring a shunt was a significant indicator for both cerebral palsy and mental retardation.

Non-white race and male gender also were significant predictors for mental retardation.

Msall said the study’s findings indicate that most extremely premature infants survive and are free of major impairments at preschool age, but that survivors still should be considered an at-risk population in need of continued follow-up.

“It appears that special high-risk groups, such as infants with hydrocephalus or sepsis, may be at even greater risk for long-term morbidity,” Msall said. “If these findings are confirmed by others, it may provide a scientific basis for following up these high-risk groups. Such strategies could better delineate which at-risk infants are most in need of active surveillance and help families identify the most appropriate resources to help their children.”

Also contributing to the study were UB researchers Germaine M. Buck, Ph.D.; Brian T. Rogers, M.D.; Deborah P. Merke, M.D.; Christina C. Wan; Nancy L. Catanzano, and William A. Zorn, Ph.D.

The research was supported in part by the Children's Guild, the New York State Office of Mental Retardation and Developmental Disabilities, and the UB School of Medicine and Biomedical Sciences.