Effects of overt hypothyroidism and thyroid autoimmunity on the risk of embryo aneuploidy and pregnancy outcomes resulting from euploid embryo transfer

This study aimed to evaluate the effects of overt hypothyroidism and thyroid autoimmunity (TAI) on the risk of embryo aneuploidy and euploid embryo transfer outcomes among women with recurrent pregnancy loss (RPL) and advanced maternal age. Patients with RPL and advanced maternal age were recruited and further classified into overt hypothyroidism and normal thyroid function groups and TAI and non-TAI groups. All the involved patients underwent assisted reproduction and preimplantation genetic testing for aneuploidy (PGT-A). Blastocyst euploidy rates detected by different PGT-A platforms and the subsequent transfer outcomes were evaluated and compared in patients with RPL and of advanced maternal age. No significant difference was found in the euploidy rates of blastocyst or euploid embryo transfer outcomes between the TAI and non-TAI groups. Euploidy rates did not significantly differ between the overt hypothyroidism group and normal thyroid function group. The incidence of pregnancy-related complications was significantly greater in the overt hypothyroidism group than in the normal thyroid function group among women with RPL; the body weights of the newborns were significantly lower in the overt hypothyroidism group than in the normal thyroid function group among women with advanced maternal age. The clinical pregnancy and live birth rates per euploid embryo transfer were lower and the miscarriage rate was higher in the overt hypothyroidism group than in the normal thyroid function group among women with RPL, but these differences were not statistically significant. TAI and overt hypothyroidism might not have adverse effects on the euploidy rates of blastocysts or blastocyst formation rates, and TAI might not have adverse effects on euploid embryo transfer outcomes among women with RPL and advanced maternal age. Overt hypothyroidism might have slightly adverse effects on euploid embryo transfer outcomes in patients with RPL.