Leptin concentrations in cord blood in normal newborn infants and offspring of diabetic mothers

Leptin has been implicated in the regulation of body weight and energy bala nce; Leptin is produced by adipocytes and placental tissue. Chronic fetal h yperinsulinemia and accelerated fetal growth with increased amounts of body fat are frequent findings in the offspring of diabetic mothers. In this st udy, we examined whether leptin levels in cord blood of infants of type 1 d iabetic mothers (n = 29), gestational diabetic mothers (n = 6) and controls (n = 96) correlated with level of maternal glucose control, maternal lepti n level at delivery, gender, fetal and placental size, and C-peptide in cor d blood at birth. Leptin was significantly elevated in infants of type 1 di abetic (24.7 ng/ml) and gestational diabetic mothers (29.3 ng/ml) as compar ed to controls (7.9 ng/ml). C-peptide was also significantly higher in infa nts of type 1 diabetic (0.91 nmol/l) and gestational diabetic mothers (0.99 nmol/l) vs controls (0.34 nmol/l). Infants of type 1 diabetic mothers with a leptin level in cord blood above the upper normal range, i.e. >30 ngl ml (n = 13), had an average maternal HbA(1c) level of 5.4% (normal < 5.5%) th at was not different from 5.2% in infants with a leptin level < 30 ng/ml (n = 15). In both neonatal groups of diabetic mothers, leptin in cord blood d id not correlate with maternal leptin concentrations, placental weight, bir thweight, gender and cord blood C-peptide. In controls, leptin in cord bloo d was higher in girls than in boys (p = 0.044) and correlated significantly with birthweight (p = 0.41, p < 0.001) and cord blood C-peptide (p = 0.44, p < 0.001) but not with maternal leptin level or placental weight. The 3-4 times higher leptin levels in the offspring of diabetic mothers than norma l could reflect increased adipose tissue mass and/or increased contribution from other sources such as placental tissue.