TSH and fT4 during pregnancy: an observational study and a review of the literature

Joosen, Annemiek M.C.P.; Linden, Ivon J. M. van der; Jong-Aarts, Neletta de; Hermus, Marieke A. A.; Ermens, A. A. M.; Groot, M.J.M. de

doi:10.1515/cclm-2015-0629

Cited by 13 publications

(8 citation statements)

References 21 publications

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“…In our study, with more than 200 women in each trimester, the results from Architect ® displayed a similar pattern to those from Cobas ® . The reference intervals of FT4 concentrations obtained by either Cobas ® and Architect ® agreed remarkably with those published for each immunoassay in large studies compared with Roche [ 12 , 14 , 15 , 16 , 17 ] and Abbott immunoassays [ 18 ]. Due to the known influence of ethnic variations on the thyroid function parameters, we only considered comparisons with studies in the European Caucasian population [ 19 ].…”

Section: Discussionsupporting

confidence: 78%

Reference Intervals of Thyroid Function Tests Assessed by Immunoassay and Mass Spectrometry in Healthy Pregnant Women Living in Catalonia

Hernández

Soldevila

Velasco

et al. 2021

JCM

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Background: Recent guidelines recommend establishing a local reference interval (RI) for thyroid function. We aimed to establish trimester-specific RIs for thyrotropin (TSH) and free thyroxine (FT4) in a cohort of healthy pregnant women in Catalonia (Spain). Methods: A prospective observational study was conducted with 332 healthy pregnant women, from the first trimester (1T) to delivery. TSH was measured using an Architect® immunoassay (Abbott) and FT4 by two immunoassays, Architect® (Abbott) and Cobas® (Roche), in the three trimesters. FT4 was also measured by liquid chromatography mass spectrometry (LC/MS/MS) in the 1T. Results: TSH (µUI/mL) increased throughout pregnancy (1T: 0.03–3.78; 2T: 0.51–3.53; 3T: 0.50–4.32; p < 0.0001) and FT4 (pmol/L) progressively decreased (Architect® 1T: 10.42–15.96; 2T: 8.37–12.74; 3T: 8.24–12.49; p < 0.0001; and Cobas®: 1T: 11.46–19.05; 2T: 9.65–14.67; 3T: 8.88–14.54; p < 0.0067). The FT4 RI during 1T determined LC/MS/MS was 8.75–18.27. Despite the 1T FT4 results measured by LC/MS/MS and with the two immunoassays being significantly correlated, the results obtained by the three methods were found to be non-interchangeable. Conclusions: We established trimester-specific RIs for TSH and for FT4 with immunoassays in our population. We also validated the 1T FT4 using LC/MS/MS to confirm the results of FT4 lower than the 2.5th percentile or higher than the 97.5th percentile.

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Section: Discussionsupporting

confidence: 78%

Reference Intervals of Thyroid Function Tests Assessed by Immunoassay and Mass Spectrometry in Healthy Pregnant Women Living in Catalonia

Hernández

Soldevila

Velasco

et al. 2021

JCM

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“…The upper limit for TSH in the present study was 3.52 mU/L during the first trimester, which is similar to the ones reported in Europe and the United States. [15–18] The values reported there are actually lower than the values reported in India 5.78 mU/L, [19] higher than the values reported in Australia 2.15 mU/L and Spain 2.65 mU/L. [20,21] In other Chinese studies, the upper-limit reference of TSH in the first trimester varies from 3.31 to 4.51 mU/L.…”

Section: Discussionmentioning

confidence: 85%

Thyroid function reference ranges during pregnancy in a large Chinese population and comparison with current guidelines

Yang

Meng

Zhang

et al. 2019

Chinese Medical Journal

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Background:A correct thyroid function reference range is important for the accurate diagnosis of thyroid disease during pregnancy. However, there is no consensus on whether thyroid function reference ranges in Chinese population should follow the America Thyroid Association (ATA) guidelines. This study aimed to establish a thyroid function reference range more suited to the Chinese population by evaluating the current thyroid function reference range in pregnant Chinese women and comparing it to the ATA guidelines.Methods:A total of 52,027 pregnant women were enrolled from January 2013 to December 2016. Thyroid stimulating hormone (TSH), free thyroxine (FT4), and thyroid peroxidase antibody (TPOAb) levels were tested during the first and third trimesters of pregnancy. Reference ranges of TSH and FT4 were established from the 2.5th and 97.5th percentiles of the TPOAb-negative population of women. The Mann-Whitney U test was used to compare thyroid hormones between the TPOAb-positive and TPOAb-negative groups.Results:We obtained that the TSH reference ranges were 0.03 to 3.52 mU/L and 0.39 to 3.67 mU/L, and the FT4 reference ranges were 11.7 to 19.7 pmol/L and 9.1 to 14.4 pmol/L, in the first and third trimester, respectively. If we used the 2011 ATA criteria about 7.0% and 4.0% pregnant women would be over diagnosed in first and third trimester, respectively, compared with local population thyroid hormone reference. When we compared our local criteria with the new 2017 ATA criteria, about 1.2% and 0.8% pregnant women would have a missed diagnosis in first and third trimester, respectively.Conclusions:Based on our data, which is in line with the current ATA guidelines, a population-based thyroid function reference range would be the first choice for diagnosis of thyroid disease during pregnancy in China. In case such population-based thyroid function reference ranges are unavailable in the east of China, our reference ranges can be adopted, if the same assay is used.Trial Registration:www.chictr.org.cn (No. ChiCTR1800014394).

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“…Dynamic changes in thyroid function during normal pregnancy due to rising human chorionic gonadotropin levels, as well as a number of other pregnancy-related physiologic changes, such as alterations in albumin and thyroxine-binding globulin concentrations, can all affect FT4 immunoassays [27][28][29][30]. Serum FT4 concentrations are known to vary during pregnancy ( Figure 3) [31], and several studies have indicated that non-pregnancy reference intervals of serum FT4 are not applicable for diagnosing thyroid diseases during pregnancy [32]. A longitudinal study of 130 healthy pregnant women reported that 36% of FT4 values recorded during the second trimester fell below the nonpregnancy lower normal limit, and this proportion rose to 41% in the third trimester [33].…”

Section: Ft4 Testing In Pregnancymentioning

confidence: 99%

Global FT4 immunoassay standardization: an expert opinion review

Kratzsch

Baumann

Ceriotti

et al. 2020

Clinical Chemistry and Laboratory Medicine (CCLM)

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ObjectivesResults can vary between different free thyroxine (FT4) assays; global standardization would improve comparability of results between laboratories, allowing development of common clinical decision limits in evidence-based guidelines.ContentWe summarize the path to standardization of FT4 assays, and challenges associated with FT4 testing in special populations, including the need for collaborative efforts toward establishing population-specific reference intervals. The International Federation of Clinical Chemistry and Laboratory Medicine Committee for Standardization of Thyroid Function Tests has undertaken FT4 immunoassay method comparison and recalibration studies and developed a reference measurement procedure that is currently being validated. Further studies are needed to establish common reference intervals/clinical decision limits. Standardization of FT4 assays will change test results substantially; therefore, a major education program will be required to ensure stakeholders are aware of the benefits of FT4 standardization, planned transition procedure, and potential clinical impact of the changes. Assay recalibration by manufacturers and approval process simplification by regulatory authorities will help minimize the clinical impact of standardization.SummarySignificant progress has been made toward standardization of FT4 testing, but technical and logistical challenges remain.OutlookCollaborative efforts by manufacturers, laboratories, and clinicians are required to achieve successful global standardization of the FT4 assays.

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TSH and fT4 during pregnancy: an observational study and a review of the literature

Cited by 13 publications

References 21 publications

Reference Intervals of Thyroid Function Tests Assessed by Immunoassay and Mass Spectrometry in Healthy Pregnant Women Living in Catalonia

Reference Intervals of Thyroid Function Tests Assessed by Immunoassay and Mass Spectrometry in Healthy Pregnant Women Living in Catalonia

Thyroid function reference ranges during pregnancy in a large Chinese population and comparison with current guidelines

Global FT4 immunoassay standardization: an expert opinion review

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