Neurologic and Developmental Disability after Extremely Preterm Birth
Nicholas S. Wood, M.B., Ch.B., Neil Marlow, D.M., Kate Costeloe, M.B., B.Chir., Alan T. Gibson, Ph.D., Andrew R. Wilkinson, M.B., Ch.B., for The EPICure Study Group
Background Small studies show that many children born as extremely preterm infants have neurologic and developmental disabilities. We evaluated all children who were born at 25 or fewer completed weeks of gestation in the United Kingdom and Ireland from March through December 1995 at the time when they reached a median age of 30 months.
Methods Each child underwent a formal assessment by an independent examiner. Development was evaluated with use of the Bayley Scales of Infant Development, and neurologic function was assessed by a standardized examination. Disability and severe disability were defined by predetermined criteria.
Results At a median age of 30 months, corrected for gestational age, 283 (92 percent) of the 308 surviving children were formally assessed. The mean (±SD) scores on the Bayley Mental and Psychomotor Developmental Indexes, referenced to a population mean of 100, were 84±12 and 87±13, respectively. Fifty-three children (19 percent) had severely delayed development (with scores more than 3 SD below the mean), and a further 32 children (11 percent) had scores from 2 SD to 3 SD below the mean. Twenty-eight children (10 percent) had severe neuromotor disability, 7 (2 percent) were blind or perceived light only, and 8 (3 percent) had hearing loss that was uncorrectable or required hearing aids. Overall, 138 children had disability (49 percent; 95 percent confidence interval, 43 to 55 percent), including 64 who met the criteria for severe disability (23 percent; 95 percent confidence interval, 18 to 28 percent). When data from 17 assessments by local pediatricians were included, 155 of the 314 infants discharged (49 percent) had no disability.
Conclusions Severe disability is common among children born as extremely preterm infants and remains a major challenge in this group of children.
Most studies that describe the outcome of premature infants are based on birth weight and thus confound the effects of extremely preterm birth with those of intrauterine growth restriction.1 However, physicians and parents contemplating the prognosis of extremely preterm infants require reliable information based on gestational age with which to plan care around the time of birth and thereafter.2,3 Information from individual hospitals has been collected from small numbers of infants over a long time and therefore includes data on infants treated in many different ways.
To collect information relevant to modern perinatal care, we conducted a prospective study of all infants born at 20 through 25 completed weeks of gestation in the United Kingdom and Ireland during a 10-month period beginning in March 1995. We obtained information on clinical findings and hospital outcome for all of the 811 extremely preterm infants born during this period who were admitted to neonatal intensive care units and discharged home.4
Disability is common among extremely premature infants who survive,5 but there are few population-based studies of the development of these infants.6,7,8,9 Here we report the results of a neurologic and developmental assessment performed a median of 30 months after the expected date of delivery in the survivors of the study cohort.