Thyroid Function Reference Values in Healthy Iodine-Sufficient Pregnant Women and Influence of Thyroid Nodules on Thyrotropin and Free Thyroxine Values

Ollero, M. D.; Toni, M.; Pineda, J.; Martínez, Juan Pablo; Espada, Mercedes; Anda, Emma

doi:10.1089/thy.2018.0324

Cited by 25 publications

(20 citation statements)

References 33 publications

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“…Our findings of significantly lower TSH level and higher FT4 level in early pregnant women compared to non-pregnant women were consistent with previous studies [25]. These significant changes of thyroid hormones levels are caused by physiological changes dur-▶Fig.…”

Section: Discussionsupporting

confidence: 93%

“…The TSH and FT4 RIs of early pregnant women as reported previously are shown in ▶ table 4 [25][26][27][28][29][30][31][32][33][34][35][36]. The RIs for TSH and FT4 of early pregnant women showed large differences across studies, and the RIs were different from detection platforms, ethnic and regions.…”

Section: Comparison Of Tsh and Ft4 Ris In Early Pregnant Individuals Across Previous Studiesmentioning

confidence: 73%

“…Various previous studies have established TSH and FT4 RIs during pregnancy [25][26][27][28][29][30][31][32][33][34][35][36], only a few studies have reported FT3 RIs for pregnant women [27,30,31,33,36]. However, all of these studies were clinical researches and used the direct method to establish RIs.…”

Section: Discussionmentioning

confidence: 99%

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Establishment of Early Pregnancy Related Thyroid Hormone Models and Reference Intervals for Pregnant Women in China Based on Real World Data

Liu

et al. 2021

Horm Metab Res

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Thyroid hormone reference intervals are crucial for diagnosing and monitoring thyroid dysfunction during early pregnancy, and the dynamic change trend of thyroid hormones during pregnancy can assist clinicians to assess the thyroid function of pregnant women. This study aims to establish early pregnancy related thyroid hormones models and reference intervals for pregnant women. We established two derived databases: derived database* and derived database#. Reference individuals in database* were used to establish gestational age-specific reference intervals for thyroid hormones and early pregnancy related thyroid hormones models for pregnant women. Individuals in database# were apparently healthy non-pregnant women. The thyroid hormones levels of individuals in database# were compared with that of individuals in database* using nonparametric methods and the comparative confidence interval method. The differences in thyroid stimulating hormone and free thyroxine between early pregnant and non-pregnant women were statistically significant (p<0.0001). The reference intervals of thyroid stimulating hormone, free thyroxine and free triiodothyronine for early pregnant women were 0.052–3.393 μIU/ml, 1.01–1.54 ng/dl, and 2.51–3.66 pg/ml, respectively. Results concerning thyroid stimulating hormone and free thyroxine reference intervals of early pregnancy are comparable with those from other studies using the same detection platform. Early pregnancy related thyroid hormones models showed various change patterns with gestational age for thyroid hormones. Early pregnancy related thyroid hormones models and reference intervals for pregnant women were established, so as to provide accurate and reliable reference basis for the diagnosing and monitoring of maternal thyroid disfunction in early pregnancy.

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Section: Discussionsupporting

confidence: 93%

Section: Comparison Of Tsh and Ft4 Ris In Early Pregnant Individuals Across Previous Studiesmentioning

confidence: 73%

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Establishment of Early Pregnancy Related Thyroid Hormone Models and Reference Intervals for Pregnant Women in China Based on Real World Data

Liu

et al. 2021

Horm Metab Res

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“…The studies included a total number of 132,794 pregnant women, comprising 68,097 samples analysed by Abbott (14 studies), 15,164 by Beckman (9 studies), 30,903 by Roche (15 studies) and 21,819 by Siemens (11 studies). Nineteen studies excluded women with antibodies to either thyroid peroxidase (TPOAb) or thyroglobulin (TgAb), 13,14,17–20,22,31,33,34,36,39,41,44,45,47,51,52,55 while 24 studies did not measure TgAbs and excluded women with positive TPOAb only. 15,16,21,23–25,27–30,32,35,37,38,40,42,43,46,48–50,53,54 The median age of patients ranged from 24 to 35 years with TSH and FT4 reference intervals determined during the first, second and third trimesters in 42, 28 and 26 studies, respectively.…”

Section: Resultsmentioning

confidence: 99%

Method-dependent variation in TSH and FT4 reference intervals in pregnancy: A systematic review

et al. 2021

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Background: Gestational TSH and FT4 reference intervals may differ according to assay method but the extent of variation is unclear and has not been systematically evaluated. We conducted a systematic review of published studies on TSH and FT4 reference intervals in pregnancy. Our aim was to quantify method-related differences in gestation reference intervals, across four commonly used assay methods, Abbott, Beckman, Roche, and Siemens. Methods: We searched the literature for relevant studies, published between January 2000 and December 2020, in healthy pregnant women without thyroid antibodies or disease. For each study, we extracted trimester-specific reference intervals (2.5â97.5 percentiles) for TSH and FT4 as well as the manufacturer provided reference interval for the corresponding non-pregnant population. Results: TSH reference intervals showed a wide range of study-to-study differences with upper limits ranging from 2.33 to 8.30 mU/L. FT4 lower limits ranged from 4.40â13.93 pmol/L, with consistently lower reference intervals observed with the Beckman method. Differences between non-pregnant and first trimester reference intervals were highly variable, and for most studies the TSH upper limit in the first trimester could not be predicted or extrapolated from non-pregnant values. Conclusions: Our study confirms significant intra and inter-method disparities in gestational thyroid hormone reference intervals. The relationship between pregnant and non-pregnant values is inconsistent and does not support the existing practice in some laboratories of extrapolating gestation references from non-pregnant values. Laboratories should invest in deriving method-specific gestation reference intervals for their population.

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“…Therefore, we considered a range of 0.13–4.16 mIU/L as a normal range for inclusion of pregnant women. [ 3 ] The optimal concentration of TSH in the serum for achieving physical and mental health is questionable, especially in pregnancy, and follow-up studies have shown an increased risk of thyroid dysfunction in individuals with normal serum TSH levels, while destructive effects have been reported for suppressed and particularly elevated serum TSH levels. [ 3 4 ] The possible consequences of minor differences in thyroid function (without achieving poor thyroid function) in the risk of weight gain during pregnancy are questionable, too.…”

Section: Introductionmentioning

confidence: 99%

The association between serum TSH concentration whithin the normal range and nutritional status in euthyroid pregnant women at the first trimester of gestation

Mardanian

Goodarzi-Khoigani

Mahmoodabad

et al. 2021

Journal of Research in Medical Sciences

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Background: Follow-up studies have shown an increased risk of thyroid dysfunction in individuals with normal serum thyroid-stimulating hormone (TSH) levels. Furthermore, the possible consequences of minor differences in thyroid function (without achieving poor thyroid function) in the risk of weight gain during pregnancy are questionable, too. The production of TSH is under the hypothalamus–pituitary control, and food is one of the most effective environmental agents that control hypothalamic–pituitary–thyroid axis activity. Regarding the few available studies, we assessed the association of minor variations of TSH concentrations and nutritional status in the first trimester of pregnancy. Materials and Methods: This cross-sectional descriptive and analytical study was performed on 150 primiparous healthy women. Demographic and family characteristics were collected using a researcher-administered questionnaire. Nutrients intake were extracted from a 72-h recall, and physical activity scores were determined by the pregnancy physical activity scale. Results: The prepregnancy body mass index (BMI) (β =0.022, P = 0.004) and participants' weight at 6–10 weeks of gestation (β =0.006, P = 0.024) were positively associated with TSH concentrations, while total physical activity score was negatively correlated (β = ‒0.006, P = 0.047). We did not find any significant association between TSH values and energy-adjusted nutrients intake ( P > 0.05). Conclusion: We suggest that differences in TSH concentrations within normal range in the first trimester are correlated with gaining weight, physical activity level, and prepregnancy BMI. TSH concentration and consequently thyroid function may influence on gestational weight gain or vice versa.

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Thyroid Function Reference Values in Healthy Iodine-Sufficient Pregnant Women and Influence of Thyroid Nodules on Thyrotropin and Free Thyroxine Values

Cited by 25 publications

References 33 publications

Establishment of Early Pregnancy Related Thyroid Hormone Models and Reference Intervals for Pregnant Women in China Based on Real World Data

Establishment of Early Pregnancy Related Thyroid Hormone Models and Reference Intervals for Pregnant Women in China Based on Real World Data

Method-dependent variation in TSH and FT4 reference intervals in pregnancy: A systematic review

The association between serum TSH concentration whithin the normal range and nutritional status in euthyroid pregnant women at the first trimester of gestation

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