Background We sought to characterize growth between birth and age 3 years in infants with hypoplastic left heart syndrome who underwent the Norwood procedure. Methods and Results We performed a secondary analysis using the Single Ventricle Reconstruction Trial database after excluding patients z score ( LAZ ) and weight‐for‐age z score ( WAZ ) at birth and age 3 years and change in WAZ over 4 clinically relevant time periods. We identified correlates of change in WAZ and LAZ using multivariable linear regression with bootstrapping. Mean WAZ and LAZ were below average relative to the general population at birth ( P P =0.05, respectively) and age 3 years ( P WAZ occurred between birth and Norwood discharge; the greatest gain occurred between stage II and 14 months. At age 3 years, WAZ and LAZ were WAZ differed among time periods. Shunt type was associated with change in WAZ only in the Norwood discharge to stage II period; subjects with a Blalock‐Taussig shunt had a greater decline in WAZ than those with a right ventricle‐pulmonary artery shunt ( P =0.002). Conclusions WAZ changed over time and the predictors of change in WAZ varied among time periods. By age 3 years, subjects remained small and three times as many children were short as were underweight (>2 SD below normal). Failure to find consistent risk factors supports the strategy of tailoring nutritional therapies to patient‐ and stage‐specific targets. Clinical Trial Registration URL: http://clinicaltrials.govTest/ . Unique identifier: NCT00115934.
