Relationship between insulin-like growth factor 1, leptin and ghrelin levels and catch-up growth in small for gestational age infants of 27-31 weeks during neonatal intensive care unit admission.

Objective: Poor post-natal growth is related to later morbidity and poor cognitive development in preterm infants. We investigated the relationship between plasma insulin-like growth factor 1 (IGF-1), leptin, active ghrelin levels and post-natal growth in preterm infants small for gestational age (SGA).

Methods: Plasma IGF-1, leptin and active ghrelin levels were measured at birth and at 2, 4, 6 and 8 weeks after birth in 42 very low birthweight (VLBW) infants (born between 27 and 31 weeks of gestation), including 14 SGA infants with extrauterine growth restriction (EUGR), 6 SGA infants without EUGR and 22 appropriate-for-gestational-age infants.

Results: At birth, IGF-1 levels in SGA infants without EUGR did not differ significantly from those in SGA infants with EUGR. However, IGF-1 levels in SGA infants without EUGR were as high as those observed in appropriate-for-gestational-age infants and were significantly different from those in SGA infants with EUGR at 4 and 8 weeks of age. Leptin and ghrelin levels did not differ significantly among the three groups at any time point.

Conclusions: IGF-1 is related to catch-up growth in SGA VLBW infants during neonatal intensive care unit admission; however, this does not appear to be the case for leptin and ghrelin. IGF-1 level monitoring may be useful for predicting EUGR in preterm VLBW infants.