Thyroid function after controlled ovarian hyperstimulation in women with and without the hyperstimulation syndrome

Objective: To investigate the impact of ovarian hyperstimulation syndrome (OHSS) on thyroid function in women without thyroid disorders and to compare it with that in women with uncomplicated controlled ovarian hyperstimulation (COH). Design: Retrospective analysis. Setting: Tertiary referral fertility center. Patient(s): A total of 77 women undergoing COH of whom 25 developed OHSS and 52 had no OHSS. Women with the presence of thyroid disorders were excluded, and only women pregnant after assisted reproductive technology were included. Intervention(s): Serum TSH and free T4 (fT4) levels were measured before and 2, 4, and 6 weeks after embryo transfer (ET), and thyroid peroxidase and thyroglobulin antibody levels were measured before ET to exclude thyroid autoimmunity. The diagnosis of OHSS was based on clinical, ultrasonographic, and biologic features. Main Outcome Measure(s): Thyroid function, OHSS. Result(s): Serum TSH and fT4 levels increased 2 weeks after ET in both study groups compared with prestimulation levels. In the OHSS group: TSH, 1.9 +/- 0.8 mIU/L vs. 3.1 +/- 1.9 mIU/L; fT4, 12.3 +/- 1.4 ng/L vs. 13.4 +/- 2.1 ng/L. In the no-OHSS group: TSH, 2.1 +/- 1.1 mIU/L vs. 2.6 +/- 1.9 mIU/L; fT4, 13.0 +/- 1.7 ng/L vs. 13.8 +/- 1.6 ng/L. The increment was comparable between both study groups. Conclusion(s): Serum TSH levels increased significantly after COH in a comparable way in both study groups, when no thyroid disorders were present. (Fertil Steril (R) 2011;96:241-5. (C) 2011 by American Society for Reproductive Medicine.)