Cord blood leptin is associated with size at birth and predicts infancy weight gain in humans. ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood.

Recent discoveries of human genetic leptin deficiency have demonstrated its importance in regulating weight gain in early childhood. To investigate whether normal variation in leptin and insulin levels in cord blood could influence infancy growth, we assayed samples from 197 infants from a representative birth cohort, who were measured at birth, 4, 8, 12 and 24 months. Cord leptin levels correlated most closely with weight and ponderal index (kg/m3) at birth, but also with length and head circumference (all p<0.0005). Independent of birth size, females had higher leptin levels than males (p<0.0005). Cord levels of leptin, but not insulin, were negatively related to weight gain (p