Objective: To evaluate the dynamical interplay between perinatal leptin concentrations and neonatal weight evolution until 3 months of age.
Methods: In a prospective observational study, maternal, cord blood and neonatal plasma leptin concentrations were correlated to birthweight and 3-month weight in 26 full-term, 20 preterm, and 17 intrauterine growth restriction (IUGR) mother-neonate couples.
Results: The median of maternal, cord blood, neonatal leptin concentrations were significantly different among the three groups (p = 0.010; <0.001; =0.041 correspondingly). In the respect of the full-term group, higher concentrations were reported in preterm and IUGR mothers and lower concentrations in cord blood and neonatal plasma. The post-hoc comparisons showed that maternal concentrations were significantly higher in the IUGR group (p = 0.005 vs full-term), cord blood concentrations resulted always significantly lower (preterm, IUGR vs full-term p < 0.001) and neonatal concentrations were significantly lower in the preterm group (p = 0.018 vs full-term). Neonatal birthweight and 3-month weight were always significantly different among groups (p < 0.001), even if preterm and IUGR still had lower weight than full-term, the percent increasing of weight between birth and 3-month demonstrated that preterm and IUGR infants have grown significantly faster, (preterm, IUGR vs full-term p < 0.001). The univariable analysis showed a maternal leptin association with offspring' birthweight (R = -38%, p = 0.006) and with 3-month weight (R = -43%, p = 0.002). Accounting for confounders, these associations lost significance. Cord blood leptin concentrations positively correlated with birthweight and with 3-month weight (both, p < 0.001). The latter correlation, when adjusting for birthweight became negative (R = -43% p < 0.001).
Conclusion: Our results showed that maternal leptin levels lost their influence on neonatal weight when considering confounders. At 3-month, once birthweight adjusted, the percent increasing of weight was statistically larger in preterm and IUGR than the full-term group and the correlation between cord blood leptin and weight turned negative, from positive at birth. These data may be a clue for further investigation on the relationship between perinatal leptin concentrations and catch-up growth.
Keywords: 3-month weight; Leptin; birthweight; intrauterine growth restriction (IUGR); preterm neonate.