ITLN1 and gestational diabetes: When we compared PBGD group versus GDM group, omentin levels were also inversely correlated with the risk of preterm birth (ß =-0.0084, p= 0.017, OR= 0.9916, 95% CI: 0.9848 - 0.9985) and an increase of omentin level by 100 ng/ml decreases the possibility of preterm birth by almost 57%.