Inclusion Criteria:  • 8-26 weeks gestation  singleton pregnancy, a positive oral glucose tolerance test written informed consent.  Exclusion Criteria:  • prior diagnosis of diabetes mellitus,  presence of infection, Presence of significant systemic disease or other severe metabolic, endocrine, medical co-morbidities history of bariatric surgery or other surgeries that induce malabsorption long-term use (>2 weeks) of systemic steroids prior to enrolment multiple pregnancy patients already using glucose lowering medications (metformin or insulin) before study entry fetal growth restriction due to placental dysfunction at study entry History of major depressive or other severe psychiatric disorders or inpatient psychiatric treatment up to 1year before enrolment Inability or refusal to comply with protocol Currently participating or having participated in an experimental study in previous three months