Azam Amirian - Department of Midwifery, School of Nursing and Midwifery, Jiroft University of Medical Sciences, Jirof, Iran
Mahin Blouchi Mahani - Department of Midwifery, School of Nursing and Midwifery, Jiroft University of Medical Sciences, Jirof, Iran.
Negar Shaterian - Student Research Committee, Jahrom University of Medical Sciences, Jahrom, Iran
Fatemeh Abdi - Assistant Professor, Non-communicable Diseases Research Center, Alborz University of Medical Sciences, Karaj, Iran.

Background: Gestational Diabetes Mellitus (GDM) is the most common medical complication in the pregnancy that leads to maternal and neonatal complications. Changes in thyroid factors can cause insulin resistance. There is currently controversy over screen method for GDM and one of the things used to diagnose GDM is thyroid function tests. This study aimed to evaluate the role of thyroid function tests in the diagnosis of GDM. Method: Systematic searches of Google Scholar, Scopus, Cochrane Library, PubMed, and Web of Science databases were conducted between ۲۰۱۰ and ۲۰۲۱. The quality of the studies were assessed by using the Newcastle Ottawa Scale checklist. Eventually, ۳۵ studies were included.Results: The results of ۱۳ studies showed a significant relationship between T۴ and GDM, the significant level of TSH was mentioned in ۱۱ studies, seven studies reported significant level of T۳ and Anti-TPO, two studies reported the significant levels of T۳ / T۴ ratio and Anti-TG, and for TG one study showed a significant relationship. The levels of T۳, T۴and T۳ / fT۴ ratio were associated with GDM. Conclusion: The increased FT۳ level, FT۳ / FT۴ ratio, and decreased FT۴ level showed the most associated with GDM among the thyroid function tests. These factors can be considered as a probable risk factor for GDM. Further research is needed.

thyroid function tests, Diabetes, Gestational, diagnosis