Trimester- and Assay-Specific Thyroid Reference Intervals for Pregnant Women in China

Xing, Jie; Yuan, Enwu; Li, Jing; Zhang, Yuchao; Meng, Xiao; Zhang, Xia; Rong, Shouhua; Lv, Zhongxing; Tian, Yuan; Jia, Liting

doi:10.1155/2016/3754213

Cited by 18 publications

(20 citation statements)

References 24 publications

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“…Whereas, the calculated reference ranges for FT 3 concentration in pregnant women (3.40-5.64 pmol/l) was marginally wider than that for non-pregnant women ( and the reference ranges for FT 3 concentration in pregnant and non-pregnant women were narrower than manufacturer's values (3.1-6.5 pmol/l). Factors such as exclusion criteria, population characteristics, immunometric assay method and iodine sufficiency status might have led to different values of such markers [38]. Previous studies [39][40][41] suggested the transformation of the results to multiples of median (MoM) in order to unitize different laboratories reports.…”

Section: Discussionmentioning

confidence: 99%

Reference Intervals for Thyroid Hormones During the First Trimester of Gestation: A Report from an Area with a Sufficient Iodine Level

et al. 2019

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The physiological changes during pregnancy modulate the endocrine system. Therefore, both the American and the European thyroid associations recommend the use of local trimester-specific reference intervals. The purpose of this study was to establish the first trimester reference intervals for thyroid function tests in the central area of Iran. We examined 436 pregnant women in their first trimester of pregnancy, and 444 non-pregnant women in a cross sectional study. Serum levels of thyroid stimulating hormone (TSH), free thyroxin (FT4), free triiodothyronine (FT3), thyroid peroxidase antibody, urinary iodine concentration (UIC), and thyroid volume were measured for all subjects. The first trimester-specific reference intervals (2.5th–97.5th percentile) were determined for 185 pregnant women and 256 non-pregnant women with negative TPOAb, adequate iodine level (UIC≥150 μg/l in pregnant and UIC≥100 μg/l in non-pregnant women), and normal thyroid examination. We calculated multiples of the median (MoM) for TFTs to normalize the obtained data. The first trimester-specific reference intervals of serum TSH, FT4, and FT3 for pregnant women were 0.20–4.60 mIU/l, 9.0–18.02 pmol/l, and 3.40–5.64 pmol/l, respectively, while the corresponding figures for non-pregnant women were 0.59–5.60 mIU/l, 9.52–19.30 pmol/l, and 3.70–5.55 pmol/l, respectively. The first and 99th percentile MoM of TSH in pregnant women in their first-trimester was 0.06–4.62. The local normal reference ranges for the first trimester of pregnancy in central region of Iran were different from the ranges suggested by the ATA.

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Section: Discussionmentioning

confidence: 99%

Reference Intervals for Thyroid Hormones During the First Trimester of Gestation: A Report from an Area with a Sufficient Iodine Level

et al. 2019

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“…The incidence of gestational diabetes mellitus and preeclampsia were negatively correlated with maternal free thyroxine (FT4) levels [ 5 ]. Also confusing is the level of thyroid hormones during pregnancy can change markedly and show a significant difference compared with those of nonpregnant people [ 6 , 7 ]. The 2017 Guidelines of the American Thyroid Association (ATA) for the Diagnosis and Management of Thyroid Disease during Pregnancy and the Postpartum have detailed the influence of increase in renal iodine excretion, thyroxine binding proteins, thyroid hormone production, and human chorionic gonadotropin (hCG) on thyroid function in the pregnant women [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

“…In the 2017 Guidelines, the ATA pointed out that the extent of TSH reduction varies significantly between different racial and ethnic groups and recommended that each institution or region should establish their own population-based and trimester-specific reference ranges [ 8 ]. However, in China, most of the reference values of thyroid hormones currently used for pregnant women are provided by foreign assay manufacturer for normal adults [ 7 ]. And there is no specialized reference data applied in Zhuang people.…”

Section: Introductionmentioning

confidence: 99%

Reference Intervals of Thyroid Hormones and Correlation of BMI with Thyroid Function in Healthy Zhuang Ethnic Pregnant Women

Sheng

Huang

Liu

et al. 2018

BioMed Research International

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Ethnic differences in the level of thyroid hormones exist among individuals. The American Thyroid Association (ATA) recommends that an institution or region should establish a specific thyroid hormone reference value for each stage of pregnancy. To date, a limited number of studies have reported the level of thyroid hormones in Chinese minorities, and the exact relationship between BMI and thyroid function in pregnant women is ill. This study was performed to establish trimester-specific reference ranges of thyroid hormones in Zhuang ethnic pregnant women and explore the role of body mass index (BMI) on thyroid function. A total of 3324 Zhuang ethnic health pregnant women were recruited in this Zhuang population-based retrospective cross-sectional study. The values of thyroid stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were determined by automatic chemiluminescence immunoassay analyzer. Multivariate linear regression and binary logistic regression were constructed to evaluate the influence of BMI on the thyroid function. The established reference intervals for the serum thyroid hormones in three trimesters were as follows: TSH, 0.02–3.28, 0.03–3.22, and 0.08-3.71 mIU/L; FT4, 10.57–19.76, 10.05–19.23, and 8.96–17.75 pmol/L; FT3, 3.51–5.64, 3.42–5.42, and 2.93–5.03 pmol/L. These values were markedly lower than those provided by the manufacturers for nonpregnant adults which can potentially result in 6.10% to 19.73% misclassification in Zhuang pregnant women. Moreover, BMI was positively correlated with isolated hypothyroxinemia (OR=1.081, 95% CI=1.007–1.161), while the correlation between the BMI and subclinical hypothyroidism was not statistically significant (OR=0.991, 95% CI=0.917–1.072). This is the first study focusing on the reference ranges of thyroid hormones in Guangxi Zhuang ethnic pregnant women, which will improve the care of them in the diagnosis and treatment. We also found that high BMI was positively associated with the risk of isolated hypothyroxinemia.

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“…Thus, in China it has been shown that prevalence of subclinical hypothyroidism using laboratory trimester specific ranges for TSH was 4% in pregnant women during the first trimester whereas this prevalence was 27.8% when a diagnostic criterion of TSH > 2.5 mU/L was used [21]. Moreover, many reported trimester-specific reference intervals for TSH were different from those recommended by 2011 ATA guidelines [22] [23]. It is therefore probable that, in our study, hypothyroidism frequency determined following 2011 ATA guidelines was overestimated.…”

Section: Discussionmentioning

confidence: 99%

Thyroid Function in Pregnant Women from a West-African Population

Awede¹,

Hounnou²,

Tshabu-Aguemon³

et al. 2018

OJMIP

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Thyroid dysfunction is frequent in pregnant women and is often associated with an increased risk of adverse maternal and fetal outcome. In the present work, thyroid function of pregnant women from Benin republic was studied. Two hundred forty (240) pregnant women, without thyroid disease history, have been included in the study. A blood sample was drawn for measurement of TSH, free T3 and free T4 serum levels. From the first to the third trimester, plasma levels of free T3 and free T4 decreased when plasma levels of TSH increased. Using recommendations of the 2011 American Thyroid Association (ATA) guidelines, thyroid dysfunction was observed in 24.17% of subjects. Hypothyroidism was present in 22.50% of subjects with 19.17% of subclinical hypothyroidism, 0.83% of overt hypothyroidism and 2.50% of hypothyroxinemia and hyperthyroidism was observed in 1.67% of subjects. An increase from 15.52% to 28.07% was observed in the frequency of hypothyroidism from the first to the third trimester of pregnancy. When an upper cut-off value of 4 mU/L was used for TSH, as recommended in the 2017 ATA guidelines, prevalence of thyroid disorders was 14.58% with 12.91% of hypothyroidism but no hypothyroidism was observed in women in the first trimester of pregnancy. A rise in hypothyroidism frequency was observed when pregnant women age increased. Hypothyroidism was very common in pregnant women in Benin. To allow accurate assessment of thyroid status in pregnant women in Benin, pregnancy specific range for plasma level of TSH and thyroid hormones should be established.

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Trimester- and Assay-Specific Thyroid Reference Intervals for Pregnant Women in China

Cited by 18 publications

References 24 publications

Reference Intervals for Thyroid Hormones During the First Trimester of Gestation: A Report from an Area with a Sufficient Iodine Level

Reference Intervals for Thyroid Hormones During the First Trimester of Gestation: A Report from an Area with a Sufficient Iodine Level

Reference Intervals of Thyroid Hormones and Correlation of BMI with Thyroid Function in Healthy Zhuang Ethnic Pregnant Women

Thyroid Function in Pregnant Women from a West-African Population

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