Cord blood leptin levels in normal pregnancies, pregnancy induced hypertension and gestational diabetes mellitus.

OBJECTIVE To compare cord blood leptin concentrations between normal pregnancy, pregnancy induced hypertension (PIH), and gestational diabetes mellitus (GDM). DESIGN Cross-sectional study. SETTING Academic institutes and a tertiary care maternal hospital. METHOD 48 newborns of normal pregnancies (N=18), pregnancy induced hypertension (N=16), and gestational diabetes mellitus (N=14) were studied. Cord blood samples were collected and newborn anthropometric indices recorded at delivery. Leptin concentrations were measured using an enzyme immunoassay. RESULTS Cord blood leptin levels were significantly different between the 3 groups (Kruskal-Wallis ANOVA; P=0.0064), and the difference resulted mainly from higher levels in GDM than in PIH [geometric mean (95% CI) for GDM: 10.89 (6.30, 18.84) vs PIH: 3.49 (2.14, 5.69) ng/ml (Dunn's multiple comparison: P<0.01). This pattern persisted even when leptin levels were normalized to the ponderal index (Kruskal-Wallis ANOVA P=0.0035; Dunn's multiple comparison: P<0.01). Leptin levels significantly and positively correlated with the ponderal index in normal pregnancy (Spearman r=0.506, p<0.05) and with birth weight in PIH (r=0.5463, p<0.05). CONCLUSION In GDM cord blood leptin levels are significantly higher, and a source other than fetal adipocytes appears to contribute to this.