About 40% of the extremely premature group have severe or moderate mental impairment at six years of age, compared to only 2% of a comparison group of classmates born full term.

Cerebral palsy, mental retardation, chronic lung disease, blindness and hearing loss are among the lifelong challenges that often face extremely premature infants -- if they survive to leave the hospital.

22 Percent Severely Disabled

Death or severe cognitive and neuromotor impairment are common outcomes for very early babies,

The research described in NEJM is the largest study to date of babies born at 22 to 25 weeks of gestation with followup to early school age. Among its findings is that 41 percent of the extremely premature group have severe or moderate mental impairment at six years of age, compared to only 2 percent of a comparison group of classmates born full term.

The results showed that 20 percent of the children had no problems, while 22 percent had severe disability, such as severe cerebral palsy (children not walking), very low cognitive scores, blindness or profound deafness.

The proportion of children with cerebral palsy with severe or moderate motor disability was 12 percent, and 24 percent had moderate disability, such as cerebral palsy (but walking), IQ/cognitive scores in the special-needs range, or lesser degrees of visual or hearing impairment.

Half Do 'Reasonably Well'

The assessment for the children in the study was not entirely bleak.

Just over one-third (34 percent) had problems considered mild, such as wearing glasses, a squint or low/normal cognitive scores.

Neil Marlow, Professor of Neonatal Medicine in the University’s School of Human Development and joint author of the paper, said: "The strength of this study is its uniqueness and its completeness enabling us to marry up all the data from birth to childhood.

"These results show that the majority of children do not have a serious physical disability, i.e., do not have cerebral palsy, blindness or deafness," Dr. Marlow pointed out, "and despite the high incidence of learning difficulties, half are doing reasonably well and keeping up with their classmates."

Number of Preterm Births Rising

"Prematurity is a common, serious problem in America and unfortunately, the number of preterm births is rising each year," said Scott D. Berns, M.D., M.P.H., FAAP, vice president for chapter programs of the March of Dimes.

"Too many babies are born extremely premature in this country, and the result is that many of them die in the hospital or suffer lifelong consequences," Dr. Berns noted.

"More research on the underlying causes of preterm birth is needed if we are to reverse this trend," Dr. Berns said. "The March of Dimes wants to prevent prematurity from occurring in the first place -- we want every birth to be a healthy one."