PARDO, INÊ S M.C.G., BRUNO GELONEZE, MARCOSA TAMBASCIA, AND ANTONIO A BARROS-FILHO. Hyperadiponectinemia in newborns: relationship with leptin levels and birth weight. Obes Res. 2004;12:521-524. Objective: Adiponectin is the only adipose-specific hormone that, despite its exclusive production by adipose tissue, is reduced in obesity and is inversely correlated with leptin levels in adults. The aim of this study was to evaluate the adiponectin concentration in umbilical cord blood at different gestational ages and to investigate its possible associations with leptin levels and birth weight. Research Methods and Procedures: Umbilical cord blood was obtained from 132 newborns (male ϭ 65, female ϭ 67, gestational age: 35 to 42 weeks). The anthropometric variables of the newborns studied were birth weight, birth length, body weight/body length, and ponderal index. Adiponectin, insulin, and leptin levels were measured by radioimmunoassay methods. Results: Adiponectin levels in males were not different from those in females (24.10 Ϯ 0.81 vs. 25.62 Ϯ 0.84 g/mL, p ϭ 0.280). Adiponectin concentrations were positively correlated with birth weight (p Ͻ 0.05), birth length (p Ͻ 0.05), body weight/body length (p Ͻ 0.05), gestational age (p Ͻ 0.01), and leptin levels (p Ͻ 0.01). Discussion: These findings indicate that adiponectin is present in umbilical cord blood after 35 to 42 weeks of gestation, with higher levels than those usually found in adults, no gender differences, and a positive correlation with birth weight and leptin. These results suggest that not only could neonatal hyperadiponectinemia be associated with the increase of adiponectin production by fetal adipose tissue but also with a possible reduction in an unknown mechanism related to the suppression of adiponectin observed in adults.

This study indicates that maternal smoking during pregnancy does not affect cord blood leptin levels in term, appropriate-for-gestational-age infants.

Our findings also reveal a significant relationship between the reported number of cigarettes smoked during pregnancy and cord blood adiponectin concentrations (p = 0.01), suggesting that this association could have a causal relationship.

Objective: To determine cord blood leptin levels in newborns appropriate for gestational age, according to gender, birth weight, birth height and ponderal index.Methods: A cross-sectional study was carried out with 132 term newborns appropriate for gestational age (68 females, 64 males), gestational age between 35-42 weeks. Data were collected through interviews with the mothers at the maternity, anthropometrycal study of the newborns, and cord blood estradiol, testosterone and leptin assays obtained immediately after birth.Results: The levels of leptin were significantly higher in females than in males (8.34±0.65 ng/ml versus 6.06±0.71 ng/ml; p = 0.000). The concentrations of estradiol and testosterone did not differ between males and females. Leptin levels were positively correlated with gestational age (r = 0.394, p < 0.01), birth weight (r = 0.466, p < 0.01), birth length (r = 0.335, p < 0.01) and ponderal index (r = 0.326, p < 0.01).Conclusions: Leptin concentration in the umbilical cord is positively correlated with gestational age, birth weight, birth height, and ponderal index, suggesting its participation in the neonatal growth process. In addition, a gender difference with higher levels of leptin in females neonates was observed, suggesting that the sexual dimorphism in relation to body composition already exists in newborns.

Leptin concentration in the umbilical cord is positively correlated with gestational age, birth weight, birth height, and ponderal index, suggesting its participation in the neonatal growth process. In addition, a gender difference with higher levels of leptin in females neonates was observed, suggesting that the sexual dimorphism in relation to body composition already exists in newborns.