More than three-quarters of children who were born before the 26th week of pregnancy are affected by cognitive and neurologic impairments by the time they reach school age, British researchers report.

“There are a number of follow-up studies of preterm babies,” Dr. Dieter Wolke told AMN Health. “However, there is no real population study of babies born at the limits of viability,” at 22 to 25 weeks into a pregnancy.

Wolke, at the University of Bristol, and his colleagues tested 241 extremely premature children at an average age of 6 and compared the results with those of a “control” group made up of 160 classmates born at full term.

Compared with the controls, 41 percent of those born extremely premature had significantly lower mental functioning, the team reports in this week’s New England Journal of Medicine. Serious impairments were more than twice as likely in boys than in girls.

Severe disability - such as incapacitating cerebral palsy, low IQ, profound hearing loss, or blindness - was diagnosed in 22 percent, while 24 percent had moderate disabilities that included less-severe cerebral palsy, somewhat below-par IQ, correctible hearing loss or impaired vision without blindness.

Only 20 percent of those born between 22 and 25 weeks had no disability.

“There is an immense amount of money invested in the neonatal care of these extremely preterm babies,” Wolke pointed out. “Our findings show they certainly have an immense need of care after they’ve been discharged from the neonatal unit.”

He believes that “if the decision is made for full treatment neonatally, then similar resources should be available to help these families afterwards to see if we can prevent learning disabilities or help them achieve a higher quality of life.”

SOURCE: New England Journal of Medicine, January 6, 2005.