Preconceptional thyrotropin level in euthyroid women is inversely associated with the live birth rate in first in vitro fertilization cycle

Abstract

Introduction: Thyroid disorders have been associated with adverse reproductive outcome. Whether the preconceptional level of thyrotropin (TSH) in euthyroid women impacts on in vitro fertilization (IVF) outcome has been debated. This study reports the outcome of first IVF cycle in euthyroid women in relation to TSH level. Material and methods: A retrospective study was conducted in women referred for fertility treatment in the period 1 January 2012 until 31 March 2014. Among the exclusion criteria were thyroid medication at referral and comorbidities. TSH was measured as part of the fertility workup, and women were followed until pregnancy loss or live birth. Outcome as well as patient characteristics were prospectively collected from a treatment database. Results: A total of 623 euthyroid women underwent their first IVF cycle. The live birth rate was 27.0% (n = 168). Comparing women with a preconceptional TSH level above vs below 2.5 mIU/L, we found lower odds for clinical pregnancy (adjusted odds ratio [aOR] 0.52; 95% CI 0.29-0.95), and lower odds for live birth (aOR 0.53; 95% CI 0.29-0.99). Conclusions: A preconceptional TSH level >2.5 mIU/L was associated with lower odds for clinical pregnancy and live birth in euthyroid healthy women undergoing first IVF cycle.