Conclusion
The thyroid hormones are involved in almost all phases of reproduction. Altered thyroid hormone levels are associated with disturbed folliculogenesis, a lower fertilization rate, and lower embryo quality. Therefore, screening for thyroid function and autoimmunity should be performed as part of the work-up of women with subfertility or miscarriage. L-thyroxine should be administered when SCH is present in women of childbearing age if they plan a pregnancy, in order to improve the likelihood of successful pregnancy outcomes. Moreover, women of childbearing age who plan to undergo COH in the immediate future, should be treated with L-thyroxine if they have positive results for serum anti-thyroid antibodies and TSH levels higher than 2.5 mIU/L, because COH places an additional strain on the thyroid gland.