171-POS

Abstract

Objectives Subclinical thyroid disorders are common in pregnant women, which are associated with adverse pregnancy outcomes. Physiological changes in pregnancy and the lack of pregnancy-specific reference ranges pose great challenge for the managements of subclinical thyroid disorders in pregnancy. We aimed to establish trimester-specific thyroid hormone reference intervals throughout pregnancy in southern Chinese population. Methods we measured the serum thyroid hormone (TSH, FT4, TPO-AB) using Abbott electrochemiluminescence immunoassay in 5589 pregnant women during 2012–2013. Patients with known thyroid disorders, autoimmune disease, recurrent miscarriage, hyperemesis gravidarum and pre-eclampsia were excluded. Trimester-specific reference ranges (2.5th, 97.5th centiles) were calculated. Results TSH median T1: 1.19 ± 0.99 mIU/L ( N = 3532), T2: 1.40 ± 1.02 mIU/L ( N = 1623), T3: 1.48 ± 1.30 mIU/L ( N = 434). FT4 median T1: 15.7 ± 3.12 pmol/L ( N = 3532), T2: 13.81 ± 2.99 pmol/L ( N = 1623), T3: 12.92 ± 2.98 pmol/L ( N = 434). TSH reference range T1: 0.01–3.55 mIU/L, T2: 0.01–4.13 mIU/L, T3: 0–4.67 mIU/L. FT4 reference range T1: 12–21.44pmol/L, T2: 10.01–19.36 pmol/L, T3: 9.29–20.31 pmol/L. TSH slightly increased throughout gestation. FT4 decreased throughout gestation. Conclusions We established pregnancy-specific thyroid function reference intervals of southern Chinese population, which is beneficial in clinical practice. Disclosures L. Liu: None. X. Zhang: None. J. Yang: None. X. Qian: None. Z. Zheng: None. X. Tang: None. H. Liu: None.