Postdischarge growth failure among extremely low birth weight infants: Correlates and consequences

To describe the prevalence and correlates of postdis-charge growth failure among extremely low birth weight (ELBW) infants (weighing less than 1 kg) and its impact on growth and development.

One hundred fifty-four ELBW infants were followed to 20 months corrected age. Growth failure was defined as a decrease in weight z score (standard deviation score) of over 0.67 during one of three periods: between 40 weeks and four months (period I), between four and eight months (period II), and between eight and 20 months corrected age (period III). A decrease in weight z score of this magnitude is comparable to crossing major growth percentiles (eg, from 25th to 10th percentile). Developmental outcomes were assessed at 20 months.

Growth failure occurred in 8% of infants during period I, 28% during period II and 12% during period III. This resulted in poorer growth attainment and motor function at 20 months. Significant predictors of growth failure included chronic lung disease during periods I and III, and cerebral palsy during period III. Growth failure during period II, while more common, was not associated with specific sequelae of prematurity. It may represent a physiological process comparable to shifts in weight percentiles in term-born infants.

Postdischarge growth failure is common among ELBW infants and contributes to poorer growth outcomes. It is associated with poorer motor outcomes when it occurs early after discharge or later in infancy. A decrease in weight z score of over 0.67 can serve as a useful indicator of growth failure in ELBW infants.