Prevalence and Clinical Impact of Thyroid Dysfunction in Pregnant Women with Gestational Diabetes Mellitus: A Case-Control Study in a Tertiary Care Setting

Background: Gestational diabetes mellitus (GDM) and thyroid disorders are two common endocrine conditions in pregnancy; each associated with adverse maternal and neonatal outcomes. Emerging evidence suggests a bidirectional relationship between glucose intolerance and thyroid dysfunction, warranting focused evaluation in high‑risk obstetric populations. Methods: A hospital‑based case–control study was conducted on 120 pregnant women (60 GDM cases, 60 controls) between 24–28 weeks of gestation. Standard oral glucose tolerance testing was used to diagnose GDM. Thyroid function was assessed via serum TSH, free T4, and free T3, with classification into overt and subclinical hypo‑ or hyperthyroidism. Associations with maternal age, BMI, parity, and obstetric/neonatal outcomes were analyzed using chi‑square and logistic regression. Results: Women with GDM had significantly higher mean TSH (5.83 vs. 3.44 mIU/L, p