Thyroid hormones influence female fertility, directly stimulating oocyte maturation and regulating prolactin and sex hormone binding globulin (SHBG) concentrations. Hyperthyroidism affects 1-2%, overt hypothyroidism 0.3%, and subclinical hypothyroidism up to 15% of women of childbearing age. Approximately 10% of euthyroid women have elevated concentrations of anti-thyroid peroxidase antibodies (aTPO) and/or anti-thyroglobulin (aTg) antibodies. Hypothyroidism can cause menstrual and ovulation disorders, and impact fertility. Studies carried out to date have not conclusively demonstrated that subclinical hypothyroidism or elevated aTPO/aTg concentrations make it harder to conceive, but they do increase the risk of pregnancy loss. Subclinical hypothyroidism and elevated aTPO/aTg concentrations without thyroid disorders are more common in polycystic ovary syndrome, premature ovarian insufficiency, and idiopathic infertility. Fertility problems are therefore an indication for screening for thyroid diseases (in females as well as in some males). A thyroid disorder diagnosed in subfertile couples should be treated appropriately, especially before attempting assisted reproductive techniques. These recommendations are intended as a guide for the management of thyroid diseases associated with infertility.
Keywords: anti-thyroid antibodies; assisted reproductive techniques; fertility; hyperthyroidism; hypothyroidism; thyroid disorders.