A Study of Thyroid Hormone Level Variations with Respect to Age, Gender, and Season in Bharuch, Gujarat

Background: Thyroid hormones play a vital role in maintaining normal reproductive function. Triiodothyronine (T3) and thyroxine (T4) regulate the growth, development, and metabolic activity of the ovaries, uterus, and placenta by binding to specific receptors present in these tissues. Consequently, thyroid dysfunction may lead to reproductive disturbances such as subfertility, infertility, menstrual irregularities, anovulation, spontaneous abortion, and delayed intrauterine development. Materials and Methods: A cross-sectional study was conducted over a one-year period from January 2025 to January 2026 among patients attending a tertiary care hospital in Bharuch, Gujarat, who underwent thyroid hormone testing. Secondary data pertaining to age, gender, and serum levels of TSH, T3, and T4 were collected and analyzed. Results: Thyroid-stimulating hormone (TSH) concentrations demonstrate an elevation during colder environmental conditions and a decline in warmer temperatures, thereby exhibiting an inverse correlation with ambient temperature. These observations imply that TSH secretion is responsive to thermal variations. Furthermore, in women of reproductive age, both TSH and thyroid hormone levels may undergo seasonal oscillations, with TSH values frequently increasing during the winter months. Additionally, statistically significant alterations in thyroid hormone profiles are evident among both males and females across various age groups in different seasonal contexts. Conclusion: It can be inferred from the findings that age, gender, and seasonal variation exert a significant and measurable influence on the circulating levels of thyroid hormones, including T3, T4, and thyroid-stimulating hormone (TSH).