Gestational diabetes mellitus (GDM) is a growing health concern that usually appears during the second and third trimester stage of pregnancy and is characterized by carbohydrate intolerance of variable severity. The aim of the present study was to scrutinize the relationship between the G972R polymorphism of the insulin receptor substrate-1 (IRS-1) gene with GDM in the Iraqi female population. One hundred and twenty of blood samples taken from healthy women (control) and women with gestational diabetes mellitus in 3rd trimester stage of pregnancy, fasting blood glucose (FBG) and HbA1c% measured to diagnose GDM, lipid profile (cholesterol, triglyceride, HDL, LDL, and VLDL), insulin concentration, insulin resistance and beta cell function to determine risk factor for GDM, molecular study consist of DNA extraction and RFLP- PCR to study Genetic variation of IRS1gene in women with GDM. The fasting blood glucose mg/dl and HbA1c% level was increased highly significantly (P<0.01) between patient (GDM) and control ( healthy women ) in 3rd trimester stage in addition lipid profile included cholesterol mg/dl, triglyceride mg/dl, LDL mg/dl , VLDL mg/dl insulin concentration and insulin resistance but level of HDL mg/dl and beta cell function were decreased highly significantly (P<0.01) between patient (GDM) and control. Also the frequency of allele T was recorded a highly significantly (P<0.01) in patient (GDM) (0.87%) while in control(0.60%), the frequency of allele C allele significant (P<0.01) in control(0.40%) while (0.13%) in patient (GDM) in third trimester stage in pregnancy in third trimester. The results of this study it can be concluded that the genetic variation of IRS1 gene was associated with gestational diabetes mellitus comparison in control (healthy women) in Iraqi women in third trimester of pregnancy.
