Association of plasma leptin levels with maternal body weight and body mass index in premature and term newborns.

Background: Leptin plays an important role in the regulation of body weight and energy metabolism in adults; its role in neonates also needs to be explored. The current study aims to determine the correlation between serum leptin concentrations and anthropometric variables in newborns and their mothers, and to examine the effects of sex, gestational age and antenatal steroid use on neonatal leptin levels.

Methods: This was a retrospective study. Blood samples were collected from 55 newborns within 24 hours of birth. Plasma leptin levels were measured by immunometric assay. The relationship between neonatal leptin levels and anthropometric parameters was determined using Pearson's correlation and further evaluated by linear regression analysis.

Results: Neonatal leptin was significantly correlated with maternal body weight (p < 0.002) and maternal body mass index (BMI) (p < 0.001). However, it was not correlated with gestational age (p = 0.130), birth weight (p = 0.097), or birth BMI (p = 0.336). The leptin levels in premature newborns (gestational age < 37 weeks; 0.69 +/- 1.82ng/mL) were significantly less than those in term newborns (gestational age > or = 37 weeks; 2.09 +/- 2.30 ng/mL, p = 0.031). There were no significant differences between sexes (p = 0.277) or in relation to antenatal steroid use (p = 0.611).

Conclusion: Neonatal serum leptin concentrations within 24 hours of birth correlated with maternal body weight and BMI, especially in premature newborns. Premature newborns had significantly lower leptin levels than full-term newborns.