In addition, the E2 levels on hCG trigger day of PCOS group is greater than that of non-PCOS group, and it is reported that the supraphysiological E2 levels during COH will also lead to the transient increase of TSH, this is mainly due to the increase of thyroxine binding protein caused by the super physiological high estrogen level in the serum, which reduces the concentration of free thyroid hormone and then causes the increase of serum TSH. The gene discussed is TG; the disease is polycystic ovary syndrome.