Pregnancy-related reference intervals for serum thyrotropin based on real-life clinical data

Simone Canovi, Silvia Vezzani, Alessandra Polese, Andrea Frasoldati, Clara Schiatti, Cristina Preda, Michele Corradini Zini, Antonio Vitiello, Marco Foracchia, Giuseppina Comitini, Lorenzo Aguzzoli, Tommaso Fasano, Luigi Vecchia

Research output: Contribution to journalArticlepeer-review


Aim: During pregnancy, thyroid homeostasis is physiologically modified, leading to altered levels of thyrotropin (TSH): hence, the adoption of pregnancy-related, population- and method-specific reference ranges is recommended. This monocentric and retrospective study was conducted to establish local pregnancy-related reference intervals for serum TSH in singleton pregnant women using real-life clinical data. Methods: We included women who measured serum TSH during pregnancy at our Laboratory over six years, excluding pregnant women with current or past history of thyroid disease, pituitary or autoimmune diseases, use of medications known to influence thyroid function, multiple and/or pathological pregnancies, BMI >30 Kg/m2. Results: We retrieved a total of 3744 TSH results. Reference limits (90% confidence intervals) for TSH (in mIU/L) are: first trimester 0.09 (0.06–0.12) − 3.16 (3.05–3.29); second trimester 0.25 (0.11–0.30) − 3.55 (3.34–3.73); third trimester 0.42 (0.15–0.48) − 3.93 (3.80–4.08). Conclusion: In conclusion, real-life clinical data could be used to establish or verify local reference intervals for TSH in pregnant women: this may reduce the risk of misclassification of pregnant women undergoing thyroid function testing.

Original languageEnglish
JournalGynecological Endocrinology
Publication statusAccepted/In press - 2020


  • hypothyroidism
  • pregnancy
  • reference intervals
  • thyroid
  • Thyrotropin
  • TSH

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Obstetrics and Gynaecology


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