背景:考虑到与妊娠相关的甲状腺生理变化以及与母体甲状腺功能异常相关的不良结局,国际指南推荐使用基于人群的妊娠中期特异性参考区间(RI)进行甲状腺检测.如果实验室中没有这些RI,在全球范围内实施建议的固定截止值仍然存在争议。为了解决这个问题,我们旨在为我们的实验室在土耳其孕妇中建立适当的促甲状腺激素(TSH)RI,并根据已建立和推荐的标准比较甲状腺功能异常的患病率.
方法:2638名孕妇,在应用与病史和产前病史相关的排除标准后,在产科门诊随访的1777名妇女被纳入参考间隔研究。通过收集2016年7月至2019年3月的数据进行了回顾性研究。通过UniCelDxI800免疫测定系统(BeckmanCoulterInc.,Brea,CA,美国)。研究设计依赖于两种方法来对孕妇进行分类:特定于三个月的孕妇和特定于亚组的孕妇;后者涉及将每个三个月分为两个亚组:T1a,T1b,T2a,T2b,T3a,T3b.在使用修改的Box-Cox幂变换方法对数据分布进行归一化后,通过参数方法得出RI的下限和上限。
结果:在妊娠早期8-12周检测到最低的TSH值,T1b亚组TSH中位值明显低于T1a亚组(P<0.05)。TSH水平随着妊娠呈逐渐升高的趋势,在T2a中明显升高,T2b,和T3b亚组与前亚组相比(P<0.05)。与美国甲状腺协会(ATA)推荐的诊断标准相比,在整个妊娠期间,甲状腺功能异常的患病率与已建立的特定于三个月和亚组的RI有显著差异(P<0.001).
结论:我们得出结论,建立妊娠和实验室特异性RI,尤其是TSH,对妊娠期甲状腺疾病的诊断至关重要,和推荐的通用截止值,这可能会导致误诊或漏诊的风险,在临床上应该谨慎。然而,关于整个怀孕期间甲状腺功能检查的波动,特定于三个月的RIs不足,并实施拆分阶段是必需的。
BACKGROUND: Considering the changes in thyroid physiology associated with pregnancy and poor outcomes related to abnormal maternal thyroid function, international
guidelines recommend using population-based trimester-specific reference intervals (RIs) for thyroid testing. If these RIs are not available in the laboratory, implementing recommended fixed cut-off values globally is still controversial. To address this issue, we aimed to establish appropriate RI of thyroid-stimulating hormone (TSH) in pregnant Turkish women for our laboratory and compare the prevalence of thyroid dysfunction based on the established and recommended criteria.
METHODS: Of 2638 pregnant women, 1777 women followed in the obstetric outpatient were enrolled in the reference interval study after applying exclusion criteria related to medical and prenatal history. A retrospective study was conducted by collecting data from July 2016 to March 2019. Serum TSH was measured by UniCel DxI 800 Immunoassay System (Beckman Coulter Inc., Brea, CA, USA). The study design relied on two approaches in order to classify pregnant women: trimester-specific and subgroup-specific; the latter involved dividing each trimester into two subgroups: T1a, T1b, T2a, T2b, T3a, T3b. The lower and upper limits of the RIs were derived by the parametric method after normalizing the data distribution using the modified Box-Cox power transformation method.
RESULTS: The lowest TSH value was detected at 8-12 weeks in early pregnancy, and the median value of TSH in the T1b subgroup was significantly lower than the T1a subgroup (P < 0.05). TSH levels showed a gradual trend of increase along with the pregnancy and increased significantly in the T2a, T2b, and T3b subgroups compared to the preceding subgroups (P < 0.05). Compared to the diagnostic criteria recommended by American Thyroid Association (ATA), the prevalence of thyroid dysfunction was significantly different from the established trimester- and subgroup-specific RIs throughout the pregnancy (P < 0.001).
CONCLUSIONS: We conclude that establishing gestation- and laboratory-specific RIs, especially for TSH, is essential for diagnosing thyroid disorders in pregnancy, and the recommended universal cut-off values, which may contribute to the risk of a misdiagnosis or a missed diagnosis, should be taken with caution in the clinical setting. However, regarding the fluctuation of thyroid function tests throughout pregnancy, trimester-specific RIs are insufficient, and implementing split phases is required.