Leptin as a possible marker of augmented metabolic risk during pregnancy

AIM: Leptin is a proteic hormone, isolated in 1994, mainly synthetized in the white adipose tissue. Aim of this study was to compare leptin concentrations in normal pregnancies with those measured in pregnancies complicated by gestational diabetes or gestational hypertension or pre-eclampsia. METHODS: We enrolled 48 pregnant women: 18 with uncomplicated pregnancy, 11 with gestational diabetes, 19 with gestational hypertension or pre-eclampsia. Leptin concentrations were measured in maternal serum at enrollment, together with insulin and cortisol, at delivery and in the immediate postpartum. At delivery serum leptin was calculated in the cord blood too. RESULTS: Fasting plasma leptin and insulin were higher in the group of patients with gestational hypertension, than in the other groups. Third-trimester maternal leptin concentrations correlated significantly with insulin levels in the group of women with gestational diabetes and in the group with gestational hypertension or pre-eclampsia, but not in the women with an uncomplicated pregnancy. CONCLUSIONS: Leptin concentrations in pregnancies complicated by hypertensive disorders are significantly higher than in normal pregnancies. The increased leptin concentrations are independent of associated proteinuria, as women with simple gestational hypertension and preeclampsia showed comparable third-trimester leptin concentrations. In both women with gestational diabetes and women with hypertensive disorders, serum leptin correlated closely with serum insulin, suggesting that the association between leptin and insulin resistance is preserved in pregnancy. Whatever the reasons for an increased maternal leptin production in pregnancies complicated by hypertension, maternal leptin homeostasis does not seem to influence foetal serum leptin concentrations, which seems to be mainly related to birth weight.