Decrease of Free Thyroxine Levels after Controlled Ovarian Hyperstimulation

Controlled ovarian hyperstimulation could lead to opposing effects on thyroid function.Therefore, in a prospective study of 65 women undergoing controlled ovarian hyperstimulation, thyroid hormones, T 4 -binding globulin, TPO antibodies, gonadotropins, estradiol, and PRL were measured before and after controlled ovarian hyperstimulation.After ovarian stimulation (mean Ϯ SE of mean): free T 4 decreased, 14.4 Ϯ 0.2 vs. 12.9 Ϯ 0.2 pmol/L (P Ͻ 0.0001); thyroidstimulating hormone increased, 2.3 Ϯ 0.3 vs. 3.0 Ϯ 0.4 mU/L (P Ͻ 0.0001); T 4 -binding globulin increased, 25.2 Ϯ 0.7 vs. 33.9Ϯ 0.9 mg/L (P Ͻ 0.0001); total T 4 increased, 98.1 Ϯ 2.3 vs. 114.6Ϯ 2.5 nmol/L (P Ͻ 0.0001); total T 3 increased, 2.0 Ϯ 0.04 vs. 2.3 Ϯ 0.07 nmol/L (P Ͻ 0.0001); TPO antibodies decreased, 370 Ϯ 233 U/mL