Relationship between human cord blood adropin levels and fetal growth

Adropin is a recently identified peptide and participates in the regulation of energy homeostasis and vascular function. The aim of this study was to examine the relationships between human cord blood adropin levels and fetal growth. A total of 159 newborns [preterm delivery (PTD), n=72; term delivery, n=87] were recruited. Adropin levels in cord blood were determined using enzyme-linked immunosorbent assay kits. Clinical information on fetal growth was collected. Adropin levels in PTD babies (median, 2028; 25th-75th, 1413-2484pg/ml) were lower than those in term delivery babies (median, 2305; 25th-75th, 1960-2684pg/ml, P=0.01). Birth weight and length z score, Ponderal index, placental length, breadth, thickness, surface area, volume and density were not significantly correlated to adropin concentrations in term delivery group. However, we found adropin concentrations were significantly correlated to gestational age at birth (Spearman's correlation coefficient=0.35, P<0.01) and placental weight (Spearman's correlation coefficient=0.24, P=0.04) in PTD group. We also found that boys had lower adropin levels than girls in PTD group (P=0.01). When the analysis was extended to the whole group (PTD and term deliveries combined), the results were similar to those for PTD group alone. After adjusting for maternal age and newborn's sex, every 100pg/ml increase of adropin concentration was significantly associated with a decreased risk of PTD (odds ratio, 0.95; 95% confidence interval, 0.91-0.99). Our study showed that cord blood adropin levels were positively correlated with gestational age and placental weight but not with other fetal growth parameters.