Decrease of free thyroxine levels after controlled ovarian hyperstimulation

Controlled ovarian hyperstimulation could lead to opposing effects on thyro id function. Therefore, in a prospective study of 65 women undergoing contr olled ovarian hyperstimulation, thyroid hormones, T-4-binding globulin, TPO antibodies, gonadotropins, estradiol, and PRL were measured before and aft er controlled ovarian hyperstimulation. After ovarian stimulation (mean +/- se of mean): free T-4 decreased, 14.4 /- 0.2 vs. 12.9 +/- 0.2 pmol/L (P < 0.0001); thyroid-stimulating hormone in creased, 2.3 +/- 0.3 vs. 3.0 +/- 0.4 mU/L (P < 0.0001); T-4-binding globuli n increased, 25.2 +/- 0.7 vs. 33.9 +/- 0.9 mg/L (P < 0.0001); total T-4 inc reased, 98.1 +/- 2.3 us. 114.6 +/- 2.5 nmol/L (P < 0.0001); total T-3 incre ased, 2.0 +/- 0.04 vs. 2.3 +/- 0.07 nmol/L (P < 0.0001); TPO antibodies dec reased, 370 +/- 233 U/mL us. 355 +/- 224 U/mL (P < 0.0001) LH decreased, 8. 1 +/- 1.1 us. 0.4 +/- 0.1 U/L (P < 0.0001); FSH did not change, 6.5 +/- 0.6 vs. 7.9 +/- 0.9 U/L (P = 0.08); human CG increased, <2 +/- 0.0 vs. 195 +/- 16 U/L (P < 0.0001); estradiol increased, 359.3 +/- 25.9 pmol/L vs. 3491.8 +/- 298.3 pmol/L (P < 0.0001); and PRL increased, 0.23 +/- 0.02 us. 0.95 /- 0.06 U/L (P < 0.0001). Because low maternal free T-4 and elevated maternal thyroid-stimulating hor mone levels during early gestation have been reported to be associated with impaired psychomotor development in the offspring, our findings indicate t he need for additional studies in the children of women who where exposed t o high levels of estrogens around the time of conception.