Objective: To determine the relationships between serum leptin levels and maternal weights in late pregnancy and cord blood leptin levels to birth-weights, C-peptide, insulin and insulin like growth factor (IGF-II).
Methods: Fifty normal pregnant women at 37-38 weeks and their newborns were studied, and 29 non-pregnant women were set as control. Venous blood was taken from women and from the cord at delivery. Blood leptin and cord blood C-peptide, insulin, and IGF-II were measured by radio-immunoassay.
Results: The average leptin level in maternal sera was (13.62 +/- 3.68) micrograms/L, significantly higher than that in the control (6.60 +/- 3.04) micrograms/L and that in cord blood (8.05 +/- 4.61) micrograms/L. Maternal leptin levels were significantly correlated with maternal weights and body mass index (BMI. r = 0.33, 0.35, P < 0.05), but not with infant birth-weights (r = 0.10, P > 0.05). Cord blood leptin levels were significantly correlated with birth-weights and BMI (r = 0.54, 0.49, P < 0.001) but have no correlation with maternal leptin levels (r = 0.19, P > 0.05). Significant difference of the cord leptin levels was not seen between the males and females. The cord blood C-peptide was (0.86 +/- 0.35) microgram/L, insulin (8.49 +/- 4.76) mU/L and IGF-II (0.218 +/- 0.076) microgram/T. Cord leptin levels were correlated with C-peptide levels (r = 0.37, P < 0.05), but not with insulin and IGF-II levels (r = 0.19, -0.14, P > 0.05).
Conclusions: Maternal leptin levels in late pregnancy were significantly higher than those in normal non-pregnant women and positively correlated with maternal weights and BMI. Cord blood leptin levels were positively correlated with birth-weights and BMI of the newborns. The leptin levels of cord blood were correlated with those of C-peptide but not insulin and IGF-II.