Thyroid function during controlled ovarian hyperstimulation as part of in vitro fertilization

Abstract

Objective To determine the exact nature and timing of alterations in thyroid function throughout controlled ovarian hyperstimulation (COH). Design Prospective cohort study. Setting University fertility clinic. Patient(s) Fifty-seven women undergoing COH as part of planned in vitro fertilization. Intervention(s) None. Main Outcome Measure(s) Timing and magnitude of change in serum thyroid hormones, including TSH, total and free T4, E2, and thyroxine-binding globulin (TBG), measured at six time points from before stimulation to 2 weeks after serum pregnancy test. Result(s) Geometric mean serum TSH increased during stimulation, peaking 1 week after hCG administration compared with baseline (2.44 vs. 1.42 mIU/L), as did free T4 (1.52 vs. 1.38 ng/dL) and TBG (32.86 vs. 21.52 μg/mL). Estradiol levels increased, peaking at hCG administration (1743.21 vs. 71.37 pg/mL). Of 50 women with baseline TSH ≤2.5 mIU/L, 22 (44.0%) had a subsequent rise in TSH to >2.5 during or after COH. The pattern of change over time in TSH concentrations was significantly influenced by baseline hypothyroidism and whether pregnancy was achieved. Conclusion(s) COH led to significant elevations in TSH, often above pregnancy appropriate targets. These findings were particularly evident in women with preexisting hypothyroidism and may have important clinical implications for screening and thyroid hormone supplementation.

Thyroid stimulating hormone levels rise after assisted reproductive technology

“…In our "positive" subjects, the mean HCG level in "pregnant" group was 364 IU/L compared to negative (being<10 mIU/L). These findings are in keeping with those of Gracia et al [14] who also found higher TSH levels after COH.…”

“…A systematic review of thyroid function during ART was inconclusive and highlighted the need for further studies [20]. Another recent study involving 57 patients showed TSH levels rise after IVF reaching a peak 1 week after HCG trigger [14].…”

Donor TSH level is associated with clinical pregnancy among oocyte donation cycles

“…Moreover, we do not routinely check thyroid antibody status or free thyroxine on patients with TSH levels < 5.0 mIU/L; therefore, these values were not consistently available for analysis. Pre-treatment TSH levels may not fully represent thyroid function during fertility treatment, as there are data suggesting that TSH levels fluctuate during stimulated cycles [5]. Since this study focused on women undergoing assisted reproductive technology at a single institution, the results may not be generalizable to women undergoing natural conception attempts or those who conceive spontaneously.…”

“…Given its relevance to reproduction and pregnancy, women with infertility are routinely screened for thyroid function with serum thyroid-stimulating hormone (TSH) prior to elective fertility treatment [4]. Since there is evidence that ovarian stimulation may impact thyroid function [5], timely recognition of thyroid disease prior to initiating fertility treatment may be essential to optimizing outcomes.…”

Impact of Controlled Ovarian Hyperstimulation on Thyroid Function

“…[3][4][5][6][7][8][9][10] Whether alterations of thyroid function during OH could influence ART and pregnancy outcomes is unclear. Several studies have evaluated thyroid parameters during OH, [11][12][13][14] or in the first month of pregnancy after OH. [15][16][17] However, the evidence concerning the effect of OH on thyroid function is contradictory, 18 probably due to the fact that alterations in thyroid function during OH are dependent on the duration and the amount of increment in E 2 levels.…”