Cord blood leptin levels: relationship to body weight, body mass index, sex and insulin and cortisol levels of maternal-newborn pairs at delivery.

To investigate leptin and to which factors it is related during the perinatal period, we measured serum leptin levels of 46 mothers at delivery, umbilical cord blood and infants on the third day of life. Maternal leptin was higher than in cord (p < 0.001), and did not correlate with maternal age, body weight, body mass index, weight gain during pregnancy, serum glucose, cholesterol, triglycerides, CPE, cortisol or HbA1c levels, nor any biochemical values or anthropometric data of the newborns (p > 0.05). In cord blood, leptin was significantly higher than in 3 day-old infants (p < 0.05), and correlated only with maternal insulin and glucose (r = 0.5, p < 0.01 and r = 0.4, p < 0.05, respectively). In 3 day-old infants, leptin did not correlate with any clinical data (p > 0.05). Leptin was not different in the two sexes (p > 0.05). Serum leptin levels were not related to adiposity of the mother-infant pairs or neonatal growth, and were not different in the two sexes during the perinatal period.