Neurodevelopmental outcomes of extreme-low-birth-weight infants born between 2001 and 2002

High Risk Follow-up Working Group (Kowloon Region)

OBJECTIVE. To report the neurodevelopmental outcomes of extreme-low-birth-weight survivors.

DESIGN. Multicentre cohort study.

SETTING. Three regional hospitals in Hong Kong.

PATIENTS. Surviving extreme-low-birth-weight infants born in 2001 and 2002 underwent neurodevelopmental, neurosensory, and functional assessment under the High Risk Follow-up Program in three Child Assessment Centres.

MAIN OUTCOME MEASURES. Demographic characteristics, neonatal diagnoses and treatment given, as well as neurodevelopmental outcomes were prospectively collected, and possible maternal and neonatal risk factors for major disability evaluated.

RESULTS. Of 81 extreme-low-birth-weight infants, 49 had undergone evaluation under the High Risk Follow-up Program. Their mean gestational age was 26.2 (standard deviation, 1.8) weeks and mean birth weight was 789 g (standard deviation, 125 g). Seventeen infants were less than 750 g and 32 were between 751 and 999 g. The rates of cerebral palsy, intellectual impairment, hearing deficit, and visual impairment were 12%, 16%, 4%, and 6%, respectively. Fifteen (31%) infants had at least one major disability. There was no association between neurodevelopmental disability and low birth weight. For neurodevelopmental disabilities, postnatal use of steroids conferred a significant risk (relative risk=7.4; 95% confidence interval, 1.9-29.2). Corresponding figures for other significant risk factors were as follows: severe grades of intraventricular haemorrhage (2.7; 1.2-5.9), presence of periventricular leukomalacia (4.5; 2.1-9.3), patent ductus arteriosus requiring ligation (2.8; 1.3-6.1), severe grades of retinopathy of prematurity (2.4; 1.0-5.6), and severe grades of necrotising enterocolitis (3.2; 1.6-6.3).

CONCLUSION. Extreme-low-birth-weight infants are at risk of major neurodevelopmental disability. Our rates of cerebral palsy, intellectual disability, and significant visual and hearing impairment were comparable to those reported in many western studies. Further longitudinal study to assess long-term neurodevelopmental outcomes in this group of children is needed.

Hong Kong Med J 2008;14:21-8

Key words: Developmental disabilities; Infant, premature; Infant, very low birth weight; Neurologic examination