Aims: This study aimed to investigate (i) the plasma ghrelin concentration at birth, (ii) the relationship of ghrelin with metabolic hormones, including leptin and insulin, and (iii) its association with anthropometric parameters, in appropriately grown preterm (23-36 weeks gestation) and term (37-42 weeks gestation) newborns.
Patients and methods: Blood samples for hormonal assay were obtained from preterm (n = 81) and term newborns (n = 40) within the first 2 h of life and before milk feeding or energy intake. The relationship between plasma ghrelin and other metabolic hormones or anthropometric parameters was evaluated.
Results: Plasma ghrelin was detectable in all studied infants and the concentrations did not differ significantly between term and preterm infants [median (interquartile range): 1.21 (0.86-1.48) nmol/l vs. 1.04 (0.71-1.51) nmol/l, P = 0.52, respectively]. There was no overall significant correlation between plasma ghrelin and gestational age, anthropometric parameters and leptin or insulin. However, when term and preterm infants were analysed independently, plasma ghrelin was inversely correlated with birth weight (r = -0.31, P = 0.05) and body length (r = -0.33, P = 0.04) in the term infant group.
Conclusions: Our findings suggested that plasma ghrelin concentrations were relatively constant at birth, between 23 and 42 weeks gestation, and ghrelin secretion did not appear to undergo gestational age-related variations. An inverse relationship between plasma ghrelin and anthropometric indices in term infants raised the possibility that ghrelin might adopt its physiological role in regulating growth and metabolism at a late stage of gestation (> or = 37 weeks gestation). This phenomenon could be beneficial to term newborns by stimulating their appetite and maintaining an adequate blood sugar level at the most critical period when nutrients from mothers are abruptly terminated after birth.