Relative hypoleptinaemia in women with mild gestational diabetes mellitus

Aims There is increasing evidence suggesting that leptin plays a major role in the regulation of energy homeostasis, as well as in the neuroendocrine and reproductive systems. Leptin is synthesized in the human placenta. The aim of this study was to relate serum leptin levels during pregnancy to glu cose tolerance, body mass index (BMI) and specific metabolic variables, suc h as specific: insulin and proinsulin. Methods A 2-h 75 g oral glucose tolerance test was performed in 221 pregnan t women at 22-29 weeks of gestation (median 25th week). Serum leptin was me asured using a radioimmunoassay. In 49 women, sequential leptin measurement s were performed (during pregnancy and Post partum (median 5 months)). Results During pregnancy serum leptin was significantly related to body wei ght (r=0.49), BMI (r=0.51), fasting immunoreactive insulin (r=0.46), specif ic insulin (r=0.43) and proinsulin (r=0.29) (all P-values <0.0001). rn wome n with mild gestational diabetes (GDM, n=55), leptin levels were lower comp ared to women with normal glucose tolerance (n = 166) after adjusting for B MT and fasting insulin (26.9 vs. 19.4 ng/ml, P = 0.0001). Leptin was signif icantly higher during pregnancy compared to post partum (mean +/- SE: 24.3 +/- 1.5 vs. 19.6 +/- 1.6 ng/ml, P = 0.0003), even after adjustment for chan ges in BMI and changes in fasting insulin (P = 0.013). Conclusions Leptin levels are elevated in pregnancy. Women with mild GDM pr esented with relative hypoleptinaemia compared to women with normal glucose tolerance.