Introduction: Preterm delivery and low birth weight (LBW) are associated with worse outcomes in neonates with hypoplastic left heart syndrome (HLHS), but an individual preterm or small neonate may actually do quite well. While gestational age (GA) and weight have been considered in isolation, understanding the interaction between risk factors and how long that risk persists may assist in determining prognosis, counseling, and future improvement in outcomes.Methods: Data from the Single Ventricle Reconstruction trial were used to analyze survival and growth outcomes to age 6 years in subjects with HLHS and other single right ventricle anomalies. Univariate and multivariable analyses examined the effects and interactions of LBW (<2500g), weight for GA, sex, and evidence of asymmetric intrauterine growth restriction with preterm (<37 weeks), early term (37-38 6/7 weeks), and term (39-40 6/7 weeks) delivery.Results: Early term delivery (n=234) was more common than term delivery (n=219), and 64 subjects were born preterm. Small for GA (SGA) was present in 41% of subjects but only 14% had LBW. Preterm delivery was associated with an increased risk of death or transplant at 6 years (HR 2.58; CI 1.43, 4.67) independent of weight for GA, sex, and LBW. For the subgroup of infants surviving to Norwood hospital discharge, the effect of preterm delivery on death or transplant persisted (HR 1.96; CI 1.10, 3.49). Early term delivery, SGA, and LBW were not independently associated with death or transplant. Asymmetric growth restriction was associated with decreased survival within the SGA group. Early term, SGA, and LBW were each associated with lower weight-for-age z-scores at age 6 years.Conclusions: Preterm delivery was independently associated with decreased survival following the Norwood procedure, even among individuals who survived to hospital discharge. SGA, LBW and early term delivery were not independently associated with survival but all negatively impacted growth at age 6 years. These data suggest the risk associated with preterm and small neonates is driven by GA and not overcome by technical and peri-operative successes.