Pregnancy profoundly alters thyroid and parathyroid function through complex physiological adaptations, with significant implications for mother and fetus. Elevated estrogen and human chorionic gonadotropin (hCG) levels substantially modify thyroid gland function and metabolism, complicating the accurate examination of thyroid functions. Hypothyroidism, particularly in subclinical form, is frequently overlooked yet associated with miscarriage, preeclampsia, placental abruption, preterm delivery, and adverse neurodevelopmental outcomes; levothyroxine therapy remains the cornerstone of management when appropriately dose-adjusted. Hyperthyroidism, although less common, especially in the context of Graves’ disease, may lead to maternal thyrotoxic crisis, gestational hypertension, fetal growth restriction, and preterm birth; trimester-specific use of antithyroid agents is critical for safe management. Thyroid nodules and differentiated thyroid cancers detected during gestation are usually indolent, with surgical intervention, when required, preferably performed in the second trimester. Parathyroid disorders, though rare, carry substantial clinical relevance, as maternal hypercalcemia may cause nephrolithiasis, pancreatitis, preeclampsia, and severe neonatal hypocalcemia; second-trimester parathyroidectomy is a surgical option in moderate to severe cases of primary hyperparathyroidism. Hypoparathyroidism and pseudohypoparathyroidism necessitate meticulous monitoring and individualized treatment of vitamin D and calcium. In summary, recognition of gestational physiological alterations, a trimester-based therapeutic strategy, and coordinated multidisciplinary care are essential to optimize maternal and perinatal outcomes in thyroid and parathyroid disease during pregnancy.