Relationship between maternal thyroid hormones and serum magnesium levels in pregnancy

This study aims to evaluate the relationship between thyroid hormones [thyroid-stimulating hormone (TSH), free T3, free T4] and serum magnesium levels according to trimesters during pregnancy. The data of a total of 75 pregnant women in the 1st, 2nd and 3rd trimesters and 25 non-pregnant women of similar age group who were admitted to a family health center and whose laboratory records included thyroid function tests and serum magnesium levels were retrospectively analyzed. Each group consisted of 25 patients. Thyroid hormones and magnesium levels were compared between the groups, and correlation analyses were performed between thyroid hormones and magnesium levels in the pregnant groups. Free T3, free T4 and magnesium levels were significantly lower in the 2nd and 3rd trimesters of pregnancy compared to non-pregnant women. TSH levels were not significantly different between the groups. Correlation analysis revealed a moderate positive and significant correlation between free T3 and magnesium levels in pregnant women (r=.340, p=.003). No significant correlation was found between TSH or free T4 and magnesium levels. Thyroid hormones and magnesium levels decrease as pregnancy progresses, and especially the positive relationship between free T3 and magnesium suggests the biological importance of magnesium in this process.