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/m.