Growth patterns and body composition in former extremely low birth weight (ELBW) neonates until adulthood: a systematic review

Preterm infants are obviously born lighter and shorter, with smaller head circumferences than normal birth weight term born neonates. They also have a different body composition. Compromised growth is associated with adverse health outcomes. Both growth retardation and accelerated growth are suggested to cause metabolic, cardiovascular, and renal complications. Reviews regarding growth and body composition in preterm infants often do not differentiate between birth weight and gestational age. The purpose of this systematic review is to assemble growth data, specific in extremely low birth weight children. Different databases were searched for studies regarding growth and body composition in former extremely low birth weight infants until adulthood. We compared height, weight, head circumference, body mass index, fat mass, lean mass, fat distribution, and body water to matched normal birth weight controls and the World Health Organization growth charts. Studies consistently reported that former extremely low birth weight neonates experience a period of accelerated postnatal growth, but they achieve lower anthropometric parameters than normal birth weight children. There is no consensus about differences in body composition and how to measure this. Conclusion: Although extremely low birth weight infants exhibit a period of catch-up growth, their growth remains retarded later in life. Further research is needed to investigate body composition and the associated risk of cardiovascular diseases or metabolic syndrome.What is Known:• Extremely low birth weight infants have lower anthropometric parameters and a different body composition at birth and term-corrected age than normal birth weight infants.• Former extremely low birth weight infants also have a higher risk on adverse cardiovascular health outcomes in later life.What is New:• After hospital discharge, extremely low birth weight neonates remain smaller and probably also lighter, with smaller head circumferences at each corrected age throughout childhood and adolescence when compared to normal birth weight infants or the World Health Organization growth charts. It is not clear whether extremely low birth weight infants reach a lower or similar body mass index score as normal birth weight infants.• There is a lack of (long-term) information on body composition in extremely low birth weight infants