Introduction: Prevalence of hypothyroidism is 25% in women in the reprodutive age group. Hypothyroidism can affect fertility due to anovulatory cycles, luteal phase defects, hyperprolactinemia and sex hormones imbalance. Some data also report that TSH levels are inversely proportional to the fertilization rate at ART (assisted reproductive technologies).
Objective: To evaluate if a relationship exists between pregnancy rates in women undergoing in vitro fertilization (IVF) and their basal thyroid stimulating hormone (TSH) levels.
Study design: We performed a retrospective cohort study in which women with known TSH level who were submitted to IVF in our Hospital during 2014 and 2015 were included. They were divided in two groups, according to their initial TSH level: > or < 2.5 mU/l. Pregnancy was defined by ultrasound visualization of gestational sac.
Results: A total of 132 women met inclusion criteria. The mean age was 34.6 years old. 75.7% of women with TSH data had oligomenorrhea. Thyroid autoantibodies were requested only in 6 cases. 36.3% of the patients had a TSH >2.5 mU/l. In that group 39% of the women had pregnancy compared to 42.8% in the group with TSH <2.5 mU/l (P=0.636).
Conclusion: No statistically significant difference was observed between the two groups concerning pregnancy rates after IVF. We cannot exclude that it is the presence of thyroid autoantibodies and not the TSH value per se that is associated with lower pregnancy rates. Further studies are needed to confirm this hypothesis.
20 - 23 May 2017
European Society of Endocrinology