Establishment of Trimester-Specific Reference Intervals for Thyroid Hormones in Korean Pregnant Women

Moon, Hee‐Won; Chung, Hee-Jung; Park, Chulmin; Hur, Mina; Yun, Yeo‐Min

doi:10.3343/alm.2015.35.2.198

Cited by 55 publications

(42 citation statements)

References 35 publications

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“…The median level of TSH showed a signi cant increasing trend from the rst trimester to the third trimester: 1.36 (0.08-3.79) mIU/L for the rst trimester, 1.60 (0.12-3.95) mIU/L for the second trimester and 1.76 (0.38-4.18) mIU/L for the third trimester (P < 0.001). This study con rmed a clear trend of increasing TSH from the rst trimester to the third trimester in pregnant women [27].…”

Section: Discussionsupporting

confidence: 75%

Establishment of assay method- and trimester-specific reference intervals for thyroid hormones during pregnancy in Chengdu, China

Huang

Li-nong

et al. 2020

Preprint

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Background: The reference intervals of thyroid hormone will change at different stages of pregnancy because of physiological alterations. On the other hand, the reference intervals of hyroid hormone will also change in different detection systems due to manufacturer’s methodology as well as different race. The objective in this study was to establish the assay method- and trimester-specific reference intervals for thyroid stimulating hormone, free thyroxine, and free triiodothyronine for pregnant women in the Chengdu.Methods: A prospective, population-based cohort study involved 23701 reference samples of pregnant women during the three trimesters and 8646 non-pregnant women with pre-pregnancy clinical and laboratory tests. The 2.5th and 97.5th percentiles were calculated as the reference intervals for thyroid stimulating hormone, free thyroxine, and free triiodothyronine at each trimester of pregnant women according to ATA Guidelines.Results: The reference interval of thyroid stimulating hormone in the 2.5th and 97.5th percentiles has a significant increasing trend from first trimester, to second trimester, and to third trimester, which was 0.08-3.79 mIU/L for first trimester, and 0.12-3.95 mIU/L for second trimester, and 0.38-4.18 mIU/L for third trimester, respectively (P < 0.001). However, the reference intervals of free thyroxine and free triiodothyronine in the 2.5th and 97.5th percentiles have significant decreasing trends from first trimester, to second trimester, and to third trimester, which were 11.87-18.83 pmol/L and 3.77-5.50 pmol/L for first trimester, and 11.22-18.19 pmol/L and 3.60-5.41 pmol/L for second trimester, and 10.19-17.42 pmol/L and 3.37-4.79 pmol/L for third trimester, respectively (both P < 0.001).Conclusion: It is necessary to establish assay method- and trimester-specific reference intervals for thyroid stimulating hormone, free thyroxine, and free triiodothyronine because the reference intervals of these thyroid hormones are significantly different at different stages of pregnancy.

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Section: Discussionsupporting

confidence: 75%

Establishment of assay method- and trimester-specific reference intervals for thyroid hormones during pregnancy in Chengdu, China

Huang

Li-nong

et al. 2020

Preprint

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“…[101112141516171819202122232425] Soldin et al . [15] showed that FT4 decreased from the 1 st to 3 rd trimester ( P < 0.001), but there was no significant difference between the second to the third trimester.…”

Section: Discussionmentioning

confidence: 99%

“…Moon et al . [24] established trimester and assay specific 2.5 th –97.5 th levels of TFT in 531 pregnant Korean women using ECL immunoassay. The TSH reference intervals were 0.01–4.10, 0.01–4.26, and 0.15–4.57 mIU/L for the first, second, and third trimester, respectively.…”

Section: Discussionmentioning

confidence: 99%

Trimester-specific reference interval for thyroid hormones during pregnancy at a Tertiary Care Hospital in Haryana, India

Rajput

Singh

Goel

et al. 2016

Indian J Endocr Metab

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Background:Reference intervals for thyroid hormone during pregnancy need to be gestational age, method, and population specific and there is need to establish trimester-specific thyroid levels for the different population across the world. The aim of this study was to establish trimester-specific reference range for thyroid hormone during pregnancy in a tertiary care center in Haryana.Materials and Methods:A total of 1430 pregnant women were recruited for the study. Participants having any history of chronic illness, goiter on physical examination, thyroid illness in the past or present, consuming thyroid medications, family history of thyroid illness, presence of anti-thyroid peroxidase antibody, poor obstetrics history were excluded from the study and reference population was identified to calculate serum free triiodothyronine (FT3), free thyroxine (FT4) and thyrotropin (TSH) for each trimester of pregnancy.Results:The 2.5–97.5th percentiles for FT3, FT4, and TSH obtained in this study were 2.53–4.54 pg/ml, 0.88–1.78 ng/ml and 0.37–3.69 μIU/ml in the first trimester, 2.0–4.73 pg/ml, 0.91–1.78 ng/ml and 0.54–4.47 μIU/ml in the second trimester, 2.01–4.01 pg/ml, 0.83–1.73 ng/ml, and 0.70–4.64 μIU/ml in the third trimester of pregnancy. Mean TSH increased and mean FT3 decreased significantly with the progression of gestational period. FT4 decreased from trimester 1–3rd, but the decrease was nonsignificant from 2nd to 3rd trimester.Conclusions:Existing results for trimester-specific reference intervals for thyroid hormones are inconsistent and cannot be extrapolated due to differences in ethnicity, maternal iodine status, laboratory assay method, and rigor for selection of reference population. Thus, establishment of reference intervals in each region is of great importance.

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“…Initial studies of pregnant women in the United States and Europe first led to recommendations for a TSH upper reference limit of 2.5 mIU/L in the first trimester and 3.0 mIU/L in the second and third trimesters [36]. During pregnancy, the Korean have demonstrated only a modest reduction in the upper reference limit [37].…”

Section: Main Issuementioning

confidence: 99%

Evaluation of Pregnancy and Thyroid Function

Chang-Eun

2018

Korean J Clin Lab Sci.

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임신과 갑상선 기능의 평가 박창은 남서울대학교 임상병리학과, 분자진단연구소During early pregnancy, before the development of a functioning thyroid gland, thyroid stimulating hormone (TSH) is a very sensitive marker of thyroid dysfunction during pregnancy. Normal values have been modified during gestation with a downward shift. The fetus is influenced by the TSH supplied by the mother. TSH and free thyroxine (FT4) concentrations vary during pregnancy and conventional units can vary between laboratories. A downward shift of the TSH reference range occurs during pregnancy, with a decrease in both the lower and upper limits of maternal TSH, relative to the typical non-pregnant TSH reference range. Each laboratory produces its own reference TSH and FT4 concentrations because there are many different assays that yield different results in pregnancy. Therefore, automated immunoassays used for serum FT4 analysis are still used widely, but the important considerations discussed above must be noted. The use of population-based, trimester-specific reference ranges remains the best way to handle this issue The slight downward shift in the upper reference range of TSH occurring in the latter first trimester (7∼12 weeks) of pregnancy, typically not observed prior to 7 weeks. Their use indicates high or low levels in a quantitative manner independent of the reference ranges. These data highlight the importance of calculating population-based pregnancy-specific thyroid parameter reference intervals. A precision medicine initiative in this area will require the collection and analysis of a large number of genetic, biological, psychosocial, and environmental variables in large cohorts of individuals. Large prospective randomized controlled trials will be needed to resolve these controversies.

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Establishment of Trimester-Specific Reference Intervals for Thyroid Hormones in Korean Pregnant Women

Cited by 55 publications

References 35 publications

Establishment of assay method- and trimester-specific reference intervals for thyroid hormones during pregnancy in Chengdu, China

Establishment of assay method- and trimester-specific reference intervals for thyroid hormones during pregnancy in Chengdu, China

Trimester-specific reference interval for thyroid hormones during pregnancy at a Tertiary Care Hospital in Haryana, India

Evaluation of Pregnancy and Thyroid Function

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