In some studies 40% of pregnant women with type I diabetes may also have thyroid dysfunction simultaneously.8 Some studies have reported high incidence of hypothyroxinemia and high Anti TPO titer in GDM.9 Prevalence of high titer of Anti TPO Ab in healthy pregnant women and type 1 diabetes also have significant difference.10 Delayed diagnosis of hypothyroidism in pregnancy leads to congenital malformations and respiratory distress in newborns of these mothers.11 This evidence concerns the gene TPO and gestational diabetes.