TG and vitamin D deficiency: According to Tanguy f et al., the pathological mechanisms of SCH during pregnancy are associated with the resulting dyslipidemia and not only with the thyroid hormone levels.14 Zhou X et al.15 showed that vitamin D deficiency in the first trimester is associated with in an increased level of TSH in the first trimester, thereby aggravating subclinical hypothyroidism.15 The results of this study are consistent with this, but vitamin D is not observed this time, which is one of the limitations of this paper.