Objective: To determine if a relationship exists between pregnancy rates obtained in patients undergoing in vitro fertilization (lVF) with donor eggs and levels of thyroid stimulating hormone greater than 2.5 mlU/L but still within a range considered normal.
Study design: Retrospective comparative cohort study. With prior approval of the Ethics Committee, 233 patients undergoing IVF with donor eggs, in a two-year period, were included. Patients were grouped depending on the thyroid stimulating hormone (TSH) level. Pregnancy rates were compared. Statistical analysis was made with the Chi-square test.
Results: Pregnancy rates, depending on the TSH level, were 56.6% in patients with TSH levels below 2.49 mU/L vs. 21.6%, in patients with levels above 2.5 mU/L. This difference was statistically significant (p < 0.001).
Conclusions: Mild abnormalities of thyroid function may adversely affect the pregnancy rates in patients un- dergoing in vitro fertilization with donor eggs. A possible alteration in endometrial function may be associated.