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

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.

Download Full-text

First- and Second-Trimester Reference Intervals for Thyroid Hormones during Pregnancy in “Rhea” Mother-Child Cohort, Crete, Greece

Journal of Thyroid Research ◽

10.4061/2011/490783 ◽

2011 ◽

Vol 2011 ◽

pp. 1-12 ◽

Cited By ~ 16

Author(s):

Polyxeni Karakosta ◽

Leda Chatzi ◽

Emmanouil Bagkeris ◽

Vasiliki Daraki ◽

Dimitris Alegakis ◽

...

Keyword(s):

Thyroid Hormones ◽

Reference Interval ◽

Reference Intervals ◽

Thyroid Stimulating Hormone ◽

Specific Reference ◽

Reference Ranges ◽

Thyroid Function Tests ◽

Second Trimester ◽

Free Triiodothyronine ◽

Reference Limit

Estimation and interpretation of thyroid function tests in pregnant women is of utmost importance for maternal, fetal and neonatal health. Our objective was to calculate laboratory- and geography-specific reference intervals for thyroid hormones during pregnancy in an iodine-sufficient area of the Mediterranean, Crete, Greece. This project was performed in the context of “Rhea” mother-child cohort. Fulfillment of extensive questionnaires and estimation of free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone (TSH), and antithyroid antibodies were performed. The reference population was defined using inclusion criteria regarding thyroidal, obstetric, and general medical status of women. Reference interval for TSH was 0.05–2.53 μIU/mL for the first and 0.18–2.73 μIU/mL for the second trimester. 6,8% and 5,9% of women in the first and second trimester, respectively, had TSH higher than the upper reference limit. These trimester-specific population-based reference ranges are essential in everyday clinical practice for the correct interpretation of thyroid hormone values and accurate classification of thyroid disorders.

Download Full-text

Trimester-Specific Reference Ranges for Thyroid Hormones in Iranian Pregnant Women

Journal of Thyroid Research ◽

10.1155/2013/651517 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 11

Author(s):

Ladan Mehran ◽

Atieh Amouzegar ◽

Hossein Delshad ◽

Sahar Askari ◽

Mehdi Hedayati ◽

...

Keyword(s):

Thyroid Hormones ◽

Pregnant Women ◽

Thyroid Function ◽

Final Analysis ◽

Reference Intervals ◽

Specific Reference ◽

Reference Ranges ◽

Thyroid Function Tests ◽

Thyroid Disorder ◽

Function Tests

Background. Due to many physiological changes during pregnancy, interpretation of thyroid function tests needs trimester-specific reference intervals for a specific population. There is no normative data documented for thyroid hormones on healthy pregnant women in Iran. The present survey was conducted to determine trimester-specific reference ranges for serum TSH, thyroxine (TT4), and triiodothyronine (TT3).Methods. The serum of 215 cases was analyzed for measurement of thyroid function tests by immunoassay method of which 152 iodine-sufficient pregnant women without thyroid autoantibodies and history of thyroid disorder or goiter were selected for final analysis. Reference intervals were defined as 5th and 95th percentiles.Results. Reference intervals in the first, second, and third trimesters were as follows: TSH (0.2–3.9, 0.5–4.1, and 0.6–4.1 mIU/l), TT4 (8.2–18.5, 10.1–20.6, and 9–19.4 μg/dl), and TT3 (137.8–278.3, 154.8–327.6, and 137–323.6 ng/dl), respectively. No correlation was found between TSH and TT4 or TT3. Significant correlation was found between TT4 and TT3 in all trimesters (r=0.35,P<0.001).Conclusion. The reference intervals of thyroid function tests in pregnant women differ among trimesters. Applying trimester-specific reference ranges of thyroid hormones is warranted in order to avoid misclassification of thyroid dysfunction during pregnancy.

Download Full-text

Population-specific reference values for thyroid hormones on the Abbott ARCHITECT i2000 analyzer

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm.2004.091 ◽

2004 ◽

Vol 42 (5) ◽

Cited By ~ 17

Author(s):

Manuel González-Sagrado ◽

Francisco Javier Martín-Gil

Keyword(s):

Thyroid Hormones ◽

Reference Values ◽

Patient Population ◽

Laboratory Data ◽

Thyroid Stimulating Hormone ◽

Specific Reference ◽

Reference Ranges ◽

Free Triiodothyronine ◽

Total Triiodothyronine ◽

Abbott Architect

AbstractReliable reference ranges are important in the interpretation of laboratory data, and it is incumbent on each laboratory to verify that the ranges they use are appropriate for the patient population they serve. The objective of this study was to determine population-specific reference ranges for thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3) and total triiodothyronine (TT3) on the Abbott ARCHITECT

Download Full-text

Establishment of trimester-specific reference intervals for thyroid stimulating hormone and free thyroxine during pregnancy in southwest China by indirect method

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/00045632211063142 ◽

2021 ◽

pp. 000456322110631

Author(s):

Ying Guo ◽

Bin Wei ◽

Wei Dai ◽

Hongjian Xie

Keyword(s):

Pregnant Women ◽

Thyroid Function ◽

Indirect Method ◽

Southwest China ◽

Thyroid Function Test ◽

Reference Intervals ◽

Thyroid Stimulating Hormone ◽

Specific Reference ◽

Test Results ◽

Function Test

Objective A series of physiological changes in thyroid function occur during pregnancy and differ from those non-pregnant women. This study aimed to establish the pregnancy-specific reference intervals of TSH and FT4 using an indirect method based on the healthy pregnant women from southwest China population. Methods Thyroid function test results which available on the Laboratory Information System (LIS) were collected from the pregnancies who visited the Obstetric Clinic or the Department of Gynecology between 1 January 2015, and 30 December 2020. We grouped the data by trimesters to establish the reference intervals (RIs) based on the clinical consensus of different levels of TSH and FT4 at different weeks of gestation. All arrangements were referenced to the document CLSI EP28-A3C. Results A total of 33,040 thyroid function test results of pregnant women, aged 31 (28,33) years were statistical analyzed. Estimated RIs for TSH and FT4 in the first, second and third trimesters corresponding to the 2.5th and 97.5th percentiles in TPOAb negative were 0.02–5.23, 0.03–5.24, 0.37–5.68 mIU/L, 11.66–20.69, 10.1–18.59, 9.85–16.86pmol/L, respectively. Conclusion This study provides trimester-specific RIs for TSH and FT4 among healthy pregnant women in southwest China which guides clinicians to diagnosis and screen for thyroid disorders in this region.

Download Full-text

Thyroid hormone profile in apparently healthy pregnant women attending in a tertiary care hospital of Bangladesh

Bangabandhu Sheikh Mujib Medical University Journal ◽

10.3329/bsmmuj.v8i2.28928 ◽

2016 ◽

Vol 8 (2) ◽

pp. 91

Author(s):

Murshed Ahamed Khan ◽

M.A. Hasanat ◽

Md. Jahangir Alam ◽

Md. Anwar Hossain ◽

Ahmed Abu Saleh ◽

...

Keyword(s):

Thyroid Hormone ◽

Pregnant Women ◽

Thyroid Function ◽

Gestational Age ◽

Tertiary Care ◽

American Thyroid Association ◽

Reference Ranges ◽

Care Hospital ◽

Cross Sectional ◽

Hormone Profile

Background: Thyroid dysfunction is not uncommon in pregnancy. It should be evaluated for better outcome of pregnancy.Objective: To observe the thyroid hormone profile in apparently euthyroid pregnant women of any trimester. Methods: This cross-sectional study investigated 350 pregnant women irrespective of gestational age [(age 24±4, m±SDyr; 1st trimester = 101, 2nd trimester=111, 3rd trimester=138) for thyroid stimulating hormone (TSH) and for free thyroxine (FT4)] to assess their thyroid function during pregnancy following the criteria of American Thyroid Association (ATA).Results: Most of the mothers were housewifes (93.1 %, 326/350) of whom 46.6% were primigravida. About 63% mother had associated goiter, 58% (204/350) were euthyroid and 41 % (142/350) were subclinical hypothyroid (SCH). Frequency of goiter (63% vs. 62%, euthyroid vs. dysfunction) was not significantly different between dysfunction and normal groups. FT4 significantly correlated with gestational age (r= - 0.131, p=0.014) and TSH level (r= - 0.612, p< 0.001).Conclusion: It is concluded that many of the apparently euthyroid pregnant mother have dysfunction as defined by ATA reference ranges for TSH and FT4. Simple screening for thyroid function may have greater implication for better pregnancy outcome.

Download Full-text

Maternal thyroid function test level during the first trimester of pregnancy at a center Yazd, Iran: A cross-sectional study

International Journal of Reproductive BioMedicine ◽

10.18502/ijrm.v19i3.8573 ◽

2021 ◽

Author(s):

Farahnaz Farzaneh ◽

Farzaneh Khastehfekr

Keyword(s):

Thyroid Hormones ◽

Thyroid Function ◽

First Trimester ◽

Cross Sectional Study ◽

Reference Intervals ◽

Reference Ranges ◽

Thyroid Function Tests ◽

Sectional Study ◽

Cross Sectional ◽

First Trimester Of Pregnancy

Background: Thyroid dysfunction is associated with negative pregnancy outcomes. There is a lack of reliable information on thyroid hormones in Iranian pregnant women, especially in Yazd. Objective: To determine the safe thyroid hormone levels in women of Yazd and also the first trimester-specific reference ranges for serum thyroid-stimulating hormone (TSH), thyroxine (T4), and triiodothyronine (T3). Materials and Methods: In this cross-sectional study, the serum of 1,148 women in the first trimester of pregnancy was analyzed. Thyroid function tests (TSH, T4, T3) were measured through radioimmunoassay (RIA) [immunoradiometric (IRMA) for TSH]. The study was conducted in Yazd, from September 2018 to November 2019. Reference intervals were defined as the 5th, 50th, and 95th percentiles. Results: The mean age of the participants was 28.78 (± 5.86 yr) (range: 15-45 yr). The thyroid hormones reference intervals in the first trimester were TSH (0.2-3.8 mIU/l), T4 (7.45-12.75, μg/dl), and T3 (100-217 ng/dl). Conclusion: The results of the present study determined a local thyroid function measurement in the first trimester of pregnancy at a center of Yazd, Iran. This could facilitate the decision-making of maternal TSH level during the first trimester of pregnancy. Key words: First pregnancy trimester, Thyrotropin, Thyroxine, Triiodothyronine.

Download Full-text

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

International Journal of Endocrinology ◽

10.1155/2016/3754213 ◽

2016 ◽

Vol 2016 ◽

pp. 1-5 ◽

Cited By ~ 7

Author(s):

Jinfang Xing ◽

Enwu Yuan ◽

Jing Li ◽

Yuchao Zhang ◽

Xiangying Meng ◽

...

Keyword(s):

Thyroid Function ◽

Chinese Women ◽

Reference Interval ◽

First Trimester ◽

Cross Sectional Study ◽

Reference Intervals ◽

Thyroid Stimulating Hormone ◽

Thyroid Peroxidase ◽

American Thyroid Association ◽

Cross Sectional

Objective. The guidelines of the American Thyroid Association (ATA) recommend an upper limit reference interval (RI) of thyroid stimulating hormone (TSH) of 2.5 mIU/L in the first trimester of pregnancy and 3.0 mIU/L in subsequent trimesters, but some reported ranges in China are significantly higher. Our study aimed to establish trimester- and assay-specific RIs for thyroid hormones in normal pregnant Chinese women. Methods. In this cross-sectional study, 2540 women with normal pregnancies (first trimester, n=398; second trimester, n=797; third trimester, n=1345) and 237 healthy nonpregnant control subjects were recruited. Serum TSH, free thyroxin (FT4), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb) levels were determined by automated chemiluminescence with an Immulite 2000 system (Siemens, Erlangen, Germany). After outliers were excluded, the 2.5–97.5th percentiles were used to define the RIs. Results. The RIs of thyroid function in the first, second, and third trimesters of pregnancy and in nonpregnant controls were 0.07–3.96, 0.27–4.53, 0.48–5.40, and 0.69–5.78 mIU/L for TSH and 9.16–18.12, 8.67–16.21, 7.80–13.90, and 8.24–16.61 pmol/L for FT4, respectively. Conclusion. The trimester- and assay-specific RIs of thyroid function during pregnancy differed between trimesters, which suggests that it is advisable to detect and avoid misclassification of thyroid dysfunction during pregnancy for women in Henan, China.

Download Full-text

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

Hormone and Metabolic Research ◽

10.1055/a-1402-0290 ◽

2021 ◽

Vol 53 (04) ◽

pp. 272-279

Author(s):

Chaochao Ma ◽

Xiaoqi Li ◽

Lixin Liu ◽

Xinqi Cheng ◽

Fang Xue ◽

...

Keyword(s):

Thyroid Hormone ◽

Thyroid Hormones ◽

Pregnant Women ◽

Early Pregnancy ◽

Gestational Age ◽

Dynamic Change ◽

Reference Intervals ◽

Thyroid Stimulating Hormone ◽

Free Thyroxine ◽

Stimulating Hormone

AbstractThyroid 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.

Download Full-text

Reference intervals for neonatal thyroid function tests in the first 7 days of life

Journal of Pediatric Endocrinology and Metabolism ◽

10.1515/jpem-2018-0007 ◽

2018 ◽

Vol 31 (10) ◽

pp. 1113-1116 ◽

Cited By ~ 4

Author(s):

Michelle S. Jayasuriya ◽

Kay W. Choy ◽

Lit K. Chin ◽

James Doery ◽

Alice Stewart ◽

...

Keyword(s):

Thyroid Function ◽

Medical Records ◽

Reference Intervals ◽

Thyroid Stimulating Hormone ◽

Primary Hypothyroidism ◽

Specific Reference ◽

Rapid Decline ◽

Thyroid Function Tests ◽

Accurate Identification ◽

Neonatal Hypothyroidism

Abstract Background: Prompt intervention can prevent permanent adverse neurological effects caused by neonatal hypothyroidism. Thyroid function changes rapidly in the first few days of life but well-defined age-specific reference intervals (RIs) for thyroid-stimulating hormone (TSH), free thyroxine (FT4) and free tri-iodothyronine (FT3) are not available to aid interpretation. We developed hour-based RIs using data mining. Methods: All TSH, FT4 and FT3 results with date and time of collection from neonates aged <7 days during 2005–2015 were extracted from the Monash Pathology database. Neonates with more than one episode of testing or with known primary hypothyroidism, identified by treating physicians or from medical records, were excluded from the analysis. The date and time of birth were obtained from the medical records. Results: Of the 728 neonates qualifying for the study, 569 had time of birth available. All 569 had TSH, 415 had FT4 and 146 had FT3 results. For age ≤24 h, 25–48 h, 49–72 h, 73–96 h, 97–120 h, 121–144 h and 145–168 h of life, the TSH RIs (2.5th–97.5th) (mIU/L) were 4.1–40.2, 3.2–29.6, 2.6–17.3, 2.2–14.7, 1.8–14.2, 1.4–12.7 and 1.0–8.3, respectively; the FT4 RIs (mean ± 2 standard deviation [SD]) (pmol/L) were 15.3–43.6, 14.7–53.2, 16.5–45.5, 17.8–39.4, 15.3–32.1, 14.5–32.6 and 13.9–30.9, respectively; the FT3 RIs (mean±2 SD) (pmol/L) were 5.0–9.4, 4.1–9.1, 2.8–7.8, 2.9–7.8, 3.5–7.2, 3.4–8.0 and 3.8–7.9, respectively. Conclusions: TSH and FT4 were substantially high in the first 24 h after birth followed by a rapid decline over the subsequent 168 h. Use of hour-based RIs in newborns allows for more accurate identification of neonates who are at risk of hypothyroidism.

Download Full-text

Gestational age-specific reference intervals for 15 biochemical measurands during normal pregnancy in China

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/0004563217738801 ◽

2017 ◽

Vol 55 (4) ◽

pp. 446-452 ◽

Cited By ~ 5

Author(s):

Yanpeng Dai ◽

Junjie Liu ◽

Enwu Yuan ◽

Yushan Li ◽

Quanxian Wang ◽

...

Keyword(s):

Pregnant Women ◽

Gestational Age ◽

Parametric Method ◽

First Trimester ◽

Normal Pregnancy ◽

Reference Intervals ◽

Specific Reference ◽

Gamma Glutamyl Transpeptidase ◽

Cross Sectional ◽

Laboratory Results

Aims Physiological changes that occur during pregnancy can influence biochemical parameters. Therefore, using reference intervals based on specimens from non-pregnant women to interpret laboratory results during pregnancy may be inappropriate. This study aimed to establish the essential reference intervals for a range of analytes during pregnancy. Methods A cross-sectional study was performed in 13,656 healthy pregnant and 2634 non-pregnant women. Fifteen biochemical measurands relating to renal and hepatic function were analysed using an Olympus AU5400 analyzer (Olympus, Tokyo, Japan). All the laboratory results were checked for outliers using Dixon’s test. Reference intervals were established using a non-parametric method. Results Alanine aminotransferase, aspartate aminotransferase, albumin, cholinesterase, creatinine, direct bilirubin, gamma-glutamyl transpeptidase, total bilirubin, total bile acid and total protein showed a decrease during the whole gestational period, while alkaline phosphatase and uric acid increased. Urea nitrogen, β2-microglobulin and cystatin-C fell significantly during the first trimester and then remained relatively stable until third trimester. Reference intervals of all the measurands during normal pregnancy have been established. Conclusions The reference intervals established here can be adopted in other clinical laboratories after appropriate validation. We verified the importance, for some measurands, of partitioning by gestational age when establishing reference intervals during pregnancy.

Download Full-text