Ramadan Fasting and Thyroid Hormone Levels in Women with Hypothyroidism

Introduction: According to some studies, Ramadan fasting causes minimal changes in the levels of thyroid hormones. The present study aimed to evaluate the impact of Ramadan fasting on the levels of thyroid hormones in fasting women with hypothyroidism and levothyroxine intake. Methods: Serum levels of free thyroxine (T4) and thyroid-stimulating hormone (TSH) were measured in 36 women with hypothyroidism aged 12-56 years, who fasted during Ramadan. Three blood samples were collected three days before Ramadan, on day 27 of Ramadan, and two months after Ramadan. In addition, the levels of hemoglobin and hematocrit (HCT) were measured during and after Ramadan. Results: The serum level of free T4 significantly decreased during Ramadan compared to before Ramadan (P<0.05). However, no significant difference was observed in the serum free T4 level before and after Ramadan. On the other hand, the TSH was higher during Ramadan compared to before Ramadan although the difference was not considered significant (normal range). TSH level reduced after Ramadan compared to during Ramadan, while no significant difference was denoted in the TSH level at the three measurement times. In addition, hemoglobin and HCT decreased significantly after Ramadan compared to during Ramadan. Conclusion: According to the results, Ramadan fasting could reduce the serum levels of free T4 in the women with hypothyroidism. However, only a slight increase was observed in the TSH levels, which was not considered significant. Further investigation is required regarding the changes caused by Ramadan fasting in the levels of hemoglobin and HCT.