Postnatal changes in concentrations of free and bound leptin

Aim-To evaluate the effect of maternal diabetes on the concentrations of fr ee and bound leptin at birth and during postnatal adaptation. Methods-Total, bound, and free leptin concentrations and the percentage of free leptin were measured in cord plasma and plasma at 3 days of age of 13 term infants of mothers with gestational diabetes mellitus (GDM) and 13 ter m infants of healthy mothers. Gestational age was 40.2 (1.4) weeks, and bir th weight was 3693 (549) g (means (SD)). Results-At birth, infants of mothers with GDM had significantly higher conc entrations of total, bound, and free leptin and a higher percentage of free leptin (all p < 0.05). In all infants, these concentrations were significa ntly lower at 3 days of age than at birth (all p < 0.003), and the differen ces in concentrations of total, bound, and free leptin between the two grou ps were no longer significant. In infants of mothers with GDM, the percenta ge of free leptin remained unchanged, and was higher (p < 0.05) than in inf ants of healthy mothers; in the latter group the percentage of free leptin significantly declined (p = 0.02). Conclusions-GDM appears to influence fetoplacental leptin metabolism. This effect may be mediated through altered maternal glucose metabolism, or insu linaemia, or both.