Trimester-specific reference intervals of thyroid function tests in Turkish pregnants

Abstract

Physiological changes in hormone levels occur in thyroid gland during pregnancy. Screening of the thyroid hormone levels and determining trimester-specific reference intervals in pregnancy are important. Guidelines recommend the use of trimester-specific reference ranges for each country. The aim of this study is to determine trimester-specific thyroid function reference intervals for pregnancy in Turkish population. In total, 5000 patients were screened out of which 1258 patients have all of fT3, fT4 and TSH levels measured, were included in the study. Patients were grouped as follows: 482 women were in first trimester, 361 women were in second trimester, and 415 women were in third trimester. All analyses were performed by means of chemiluminescence methods (Liaison^®; DiaSorin S.p.A., Saluggia, Italy). The TSH reference intervals were 0.005–3.65, 0.01–3.63, and 0.2–3.46 mIU/L at the first, the second, and the third trimesters of pregnancy, respectively. The fT4 reference intervals were 0.72–1.79, 0.71–1.26, and 0.65–1.12 ng/dL at the first, the second, and the third trimesters, respectively. The fT3 reference intervals were 2.45–4.03, 2.37–3.85, and 2.31–3.77 ng/dL at the first, the second, and the third trimesters, respectively. It is crucial to determine population- and gestational-specific reference intervals for trustworthy treatment of pregnants.

摘要

妊娠期间甲状腺激素水平会发生生理性变化。筛查甲状腺激素水平和确定妊娠期特定参考值范围是及其重要的。指南建议每个国家应当针对妊娠初期、中期、晚期采用特定的参考值范围。本研究的目的是确定妊娠不同期间的土耳其人群的甲状腺功能的参考值范围。本研究共筛选了5000例患者, 其中1258例患者已检测fT3、fT4和TSH水平。患者分组如下：妊娠早期482例, 妊娠中期361例, 妊娠晚期415例。所有分析均采用化学发光法（LiaisonV R; DiaSorin S.p.A., Saluggia, 意大利）。TSH参考区间分别为妊娠初期为0.005-3.65 mIU/L、妊娠中期为0.01-3.63 mIU/L、妊娠晚期为0.2-3.46 mIU/L。fT4的参考区间在妊娠初期为0.72-1.79 ng/dL、妊娠中期为0.71-1.26 ng/dL、妊娠晚期为0.65-1.12 ng/dL。fT3的参考区间在妊娠初期为2.45-4.03 ng/dL、妊娠中期为2.37-3.85 ng/dL、妊娠晚期为2.31-3.77 ng/dL。确定人群和妊娠期特异性参考值范围对于妊娠期间治疗至关重要。

The Chinese abstracts are translated by Prof. Dr. Xiangyan Ruan and her team: Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing 100026, China.

Keywords:

• Pregnancy
• thyroid function tests
• reference intervals

Disclosure statement

The authors have nothing to disclose.