Neonatal Cord Blood Leptin: Its Relationship to Birth Weight

ABSTRACT

PURPOSE: The purpose of this study was to correlate birth weight, skinfold thickness, gestational age, BMI and ponderal index of neonates and maternal status with cord serum leptin concentration. METHODS: Sixty newborns were enrolled in this study. Standard growth curves were used to categorize infants as appropriate(AGA), large(LGA), or small for gestational age(SGA). Gestational age, birth weight, length, skinfold thickness, and placental weight were measured. Maternal age, weight, and height were measured. Cord blood and maternal venous blood samples were collected, and serum was separated and stored at -20degrees C. Leptin was measured by radioimmunoassay. RESULTS: Mean leptin concentration in cord blood was 4.38+/-2.65ng/ml and closely related to size and adiposity at birth, but not to gestational age. Cord blood leptin level was significantly lower in SGA infants(1.64+/-0.58ng/ml) and higher in LGA infants(5.53+/-2.64ng/ml) than in AGA infants (4.99+/-2.37ng/ml)(P<0.05). Mean leptin concentration in maternal blood(13.01+/-8.28ng/ml) was significantly higher than in cord blood(P<0.001), and maternal obesity and serum leptin concentrations did not correlate with cord blood leptin concentrations. No gender differences were found in cord blood leptin. CONCLUSION: The leptin level of cord blood is highly correlated to the birth weight and the size of adipose tissue. Leptin may be responsible for the regulation of body mass of human neonates and can be used as a marker of fetal growth.