Mild Anemia May Affect Thyroid Function in Pregnant Chinese Women During the First Trimester

BackgroundPregnant women are often susceptible to anemia, which can damage the thyroid gland. However, compared with moderate and severe anemia, less attention has been paid to mild anemia. The purpose of this study was to evaluate the effect of mild anemia on the thyroid function in pregnant women during the first trimester.MethodsA total of 1,761 women in the first trimester of their pregnancy were enrolled from Shenyang, China, and divided into mild anemia and normal control groups based on their hemoglobin levels. Thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) levels were compared between the two groups.ResultsThe TSH levels of pregnant women with mild anemia were higher than those of pregnant women without mild anemia (p < 0.05). Normal control women were selected to set new reference intervals for TSH, FT3, and FT4 levels during the first trimester, which were 0.11–4.13 mIU/l, 3.45–5.47 pmol/l, and 7.96–16.54 pmol/l, respectively. The upper limit of TSH 4.13 mU/l is close to the upper limit 4.0 mU/l recommended in the 2017 American Thyroid Association (ATA) guidelines, indicating that exclusion of mild anemia may reduce the difference in reference values from different regions. Mild anemia was related to 4.40 times odds of abnormally TSH levels (95% CI: 2.84, 6.76) and 5.87 increased odds of abnormal FT3 (95% CI: 3.89, 8.85). The proportion of hypothyroidism and subclinical hypothyroidism in patients with mild anemia was higher than that in those without anemia (0.6% vs. 0, p = 0.009; 12.1% vs. 1.9%, p < 0.001). Mild anemia was related to 7.61 times increased odds of subclinical hypothyroidism (95% CI: 4.53, 12.90).ConclusionsMild anemia may affect thyroid function during the first trimester, which highlights the importance of excluding mild anemia confounding when establishing a locally derived specific reference interval for early pregnancy.

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

BioMed Research International ◽

10.1155/2018/2032413 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Yonghong Sheng ◽

Dongping Huang ◽

Shun Liu ◽

Xuefeng Guo ◽

Jiehua Chen ◽

...

Keyword(s):

Thyroid Hormones ◽

Pregnant Women ◽

Thyroid Function ◽

Reference Intervals ◽

Thyroid Stimulating Hormone ◽

Specific Reference ◽

American Thyroid Association ◽

Reference Ranges ◽

Free Triiodothyronine ◽

Cross Sectional

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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Gestation specific reference intervals for thyroid function tests in pregnancy

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2015-0569 ◽

2016 ◽

Vol 54 (8) ◽

Cited By ~ 6

Author(s):

Süleyman Akarsu ◽

Filiz Akbiyik ◽

Eda Karaismailoglu ◽

Zeliha Gunnur Dikmen

Keyword(s):

Pregnant Women ◽

Thyroid Function ◽

First Trimester ◽

Reference Intervals ◽

Specific Reference ◽

Thyroid Function Tests ◽

Second Trimester ◽

Third Trimester ◽

The Third ◽

Function Tests

AbstractThyroid function tests are frequently assessed during pregnancy to evaluate thyroid dysfunction or to monitor pre-existing thyroid disease. However, using non-pregnant reference intervals can lead to misclassification. International guidelines recommended that institutions should calculate their own pregnancy-specific reference intervals for free thyroxine (FT4), free triiodothyronine (FT3) and thyroid-stimulating hormone (TSH). The objective of this study is to establish gestation-specific reference intervals (GRIs) for thyroid function tests in pregnant Turkish women and to compare these with the age-matched non-pregnant women.Serum samples were collected from 220 non-pregnant women (age: 18–48), and 2460 pregnant women (age: 18–45) with 945 (39%) in the first trimester, 1120 (45%) in the second trimester, and 395 (16%) in the third trimester. TSH, FT4 and FT3 were measured using the Abbott Architect i2000SR analyzer.GRIs of TSH, FT4 and FT3 for first trimester pregnancies were 0.49–2.33 mIU/L, 10.30–18.11 pmol/L and 3.80–5.81 pmol/L, respectively. GRIs for second trimester pregnancies were 0.51–3.44 mIU/L, 10.30–18.15 pmol/L and 3.69–5.90 pmol/L. GRIs for third trimester pregnancies were 0.58–4.31 mIU/L, 10.30–17.89 pmol/L and 3.67–5.81 pmol/L. GRIs for TSH, FT4 and FT3 were different from non-pregnant normal reference intervals.TSH levels showed an increasing trend from the first trimester to the third trimester, whereas both FT4 and FT3 levels were uniform throughout gestation. GRIs may help in the diagnosis and appropriate management of thyroid dysfunction during pregnancy which will prevent both maternal and fetal complications.

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SUBCLINICAL HYPOTHYROIDISM IN PREGNANCY; IS THERE A NEED FOR PHARMACOLOGICAL INTERVENTION?

International Journal of Pharmacy and Pharmaceutical Sciences ◽

10.22159/ijpps.2017v9i3.16542 ◽

2017 ◽

Vol 9 (3) ◽

pp. 186

Author(s):

Shripad Hebbar ◽

Sahan Kumar ◽

Sapna Amin ◽

Sneha Doizode

Keyword(s):

Gestational Diabetes ◽

Pregnant Women ◽

Preterm Delivery ◽

Subclinical Hypothyroidism ◽

First Trimester ◽

Pharmacological Intervention ◽

Complication Rates ◽

Geographic Population ◽

First Trimester Of Pregnancy ◽

Tsh Levels

Objective: To find the prevalence of subclinical hypothyroidism in the first trimester of pregnancy and to compare the maternal and perinatal outcome in them with euthyroid mothers.Methods: The present study was a prospective observational case-control study done in a tertiary hospital over the period of one and half years. Pregnant women in the first trimester of pregnancy were tested for Thyroid Stimulating Hormone (TSH) levels and those who had TSH>2.5mIU/l, free T3 and free T4 estimation was carried out on the same sample. A total of 171 women could be followed up till delivery and their first-trimester thyroid profile was available for analysis. They were grouped into two groups, Group 1: all women with TSH level>2.5 mIU/l, considered to be hypothyroid (n=79), Group 2: women with euthyroid status with TSH levels 0.1 to 2.5 mIU/l (n=95). All the neonates delivered in the first group had cord blood TSH estimation.Results: In the study period, there were 2632 deliveries. The number of pregnant women with first trimester TSH levels>2.5 mIU/l were 79, giving the prevalence rate of 3 % for subclinical hypothyroidism during pregnancy. The obstetric complications observed were gestational hypertension 3.8%, gestational diabetes 6.3%, placenta praevia1.3% and preterm delivery 7.6%. The perinatal complications included Intrauterine growth restriction (IUGR) 1.3%, Low Birth Weight (LBW) 3.8%, perinatal asphyxia 2.5% and neonatal hypothyroidism 1.3%. Only preterm delivery appeared to be significantly associated with subclinical hypothyroidism.Conclusion: The observed complication rates were much similar, in fact, lesser with gestational diabetes, pregnancy hypertension, IUGR, LBW compared to global and Indian prevalence rates. This indicates that the cut-off for diagnosing subclinical hypothyroidism should be derived from TSH assays from the local geographic population and should guide the treating physician to establish appropriate TSH ranges where definite therapeutic intervention is required to improve the maternal and foetal outcome.

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First trimester thyroid function in pregnant women residing in Saint Petersburg (Russia): reference values and risk of gestational diabetes

Diabetes Mellitus ◽

10.14341/dm9283 ◽

2018 ◽

Vol 21 (1) ◽

pp. 34-41

Author(s):

Polina V. Popova ◽

Ekaterina S. Shilova ◽

Alexandra S. Tkachuk ◽

Alexandra V. Dronova ◽

Anna D. Anopova ◽

...

Keyword(s):

Gestational Diabetes ◽

Pregnant Women ◽

Reference Values ◽

Subclinical Hypothyroidism ◽

Reference Interval ◽

First Trimester ◽

Specific Reference ◽

Thyroid Status ◽

Saint Petersburg ◽

Increased Risk

Background. Subclinical hypothyroidism during pregnancy and gestational diabetes mellitus (GDM) is known to be associated with maternal and child morbidity. The concept of subclinical dysfunction of the thyroid gland in pregnant women depends on the population-specific and trimester-specific reference values so fixed universal cutoff concentrations for thyroid-stimulating hormone (TSH) that were recommended earlier now are put under the question. Population-specific and trimester-specific reference values have not been defined for pregnant women residing in Saint Petersburg. The data concerning the association of maternal thyroid status with GDM development are controversial. Aims. The aim of the study was to determine the reference values of TSH and free thyroxin (fT4) in the first trimester of pregnancy in women living in St. Petersburg, and to assess the relationship between thyroid status and the risk of subsequent development of GDM. Materials and methods. The levels of TSH, fT4 and thyroid peroxidase antibodies (TPO-Ab) were analyzed in 503 pregnant women before the 14th week of gestation. The women underwent oral glucose tolerance test (OGTT) at 2428 weeks to find out those with GDM. The association between thyroid function, thyroid autoimmunity and the risk of GDM we estimated. Results. The reference values for TSH were 0.07 4.40 mU /L, and for fT4 11.7 20.3 pmol/L. The prevalence of subclinical hypothyroidism in the 503 pregnant women was 16.9% according to the diagnostic criteria of TSH 2.5 mIU / L and 3.8% using our calculated reference interval. Hypothyroxinemia was registered in 5,3% using reference values recommended by diagnostic tests manufacturer and in 2,8% according to our calculated reference interval for fT4. GDM was diagnosed in 23% of women. Logistic regression analysis showed associations of hypothyroxinemia and TPO-Ab-positivity with the increased risk of GDM that remained significant after adjustments on age and body mass index (BMI) [adjusted OR (95% CI) = 7.39 (1.2742.93) for hypothyroxinemia, p=0.026; and adjusted OR (95% CI) = 2.02 (1.014.04) for TPO-Ab-positivity, p=0.047). Conclusions. Reference intervals for first trimester TSH and fT4 have been established for pregnant women living in St. Petersburg. Hypothyroxinemia and TPO-Ab-positivity were associated with the increased risk of GDM.

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Assessment of Thyroid Function During First-Trimester Pregnancy: What Is the Rational Upper Limit of Serum TSH During the First Trimester in Chinese Pregnant Women?

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2013-1674 ◽

2014 ◽

Vol 99 (1) ◽

pp. 73-79 ◽

Cited By ~ 110

Author(s):

Chenyan Li ◽

Zhongyan Shan ◽

Jinyuan Mao ◽

Weiwei Wang ◽

Xiaochen Xie ◽

...

Keyword(s):

Pregnant Women ◽

Thyroid Function ◽

First Trimester ◽

First Trimester Pregnancy ◽

Upper Limit ◽

Trimester Pregnancy ◽

Serum Tsh

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Prevalence of anti-thyroid peroxidase antibodies in the first trimester pregnancy and its impact on maternal and fetal outcomes in a tertiary care centre in Bangalore

Indian Journal of Obstetrics and Gynecology Research ◽

10.18231/j.ijogr.2021.039 ◽

2021 ◽

Vol 8 (2) ◽

pp. 182-187

Author(s):

Shruthi H S ◽

Nalini Arunkumar ◽

Ravi N Patil

Keyword(s):

Pregnant Women ◽

Tertiary Care ◽

First Trimester ◽

Thyroid Stimulating Hormone ◽

P Value ◽

Thyroid Peroxidase ◽

American Thyroid Association ◽

Tertiary Care Centre ◽

Mother And Child ◽

Tsh Levels

: Hypothyroidism during pregnancy has an adverse effect on both mother and child. The maternal and foetal risk is higher in TPOAb (Thyroid peroxidase antibody) positive women compared to women with negative TPO Ab. The recent ATA (American Thyroid Association) guidelines recommend that pregnant women with TSH (Thyroid Stimulating Hormone) concentration above 2.5mU/L should be evaluated for TPOAb status and LT4(levothyroxine) treatment should be considered with TSH values between 2.5mU/L and 4.0mU/L only when TPOAb status is positive.: All the pregnant women booked in first trimester underwent testing for TSH levels and subsequently for anti TPO Ab if TSH levels were between 2.5-4 mIU/ml. The hospital based prevalence of women with anti TPO Ab positive status was determined. These pregnancies were followed till term and the maternal and foetal complications associated with TPO Ab positive and negative status were compared. Total of 400 pregnant women were included. The hospital prevalence of women with anti TPO antibodies in first trimester of pregnancy with TSH values between 2.5- 4 mIU/ml was found to be 23.5%. Anti TPO antibody positive status was significantly more associated with antenatal complications especially GDM and IUGR as compared to patients with anti TPO antibody negative status (47.8% v/s 23.2%, p value 0.001).: Women with TPO Ab positive status are to be vigilantly monitored for early detection and management of various antenatal complications. Determining anti TPO Ab status helps in avoiding unnecessary treatment of the women with TPO Ab negative status and TSH between 2.5-4mIU/ml.

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Subclinical hypothyroidism (SCH) in first trimester of pregnancy.

The Professional Medical Journal ◽

10.29309/tpmj/2020.27.11.4495 ◽

2020 ◽

Vol 27 (11) ◽

pp. 2474-2477

Author(s):

Kashif Ali Khan ◽

Muhammad Saleem Akhter ◽

Kehkashan Fatima ◽

Muhammad Waqar Saleem

Keyword(s):

Pregnant Women ◽

Subclinical Hypothyroidism ◽

Neonatal Death ◽

Placental Abruption ◽

First Trimester ◽

Free T4 ◽

Cross Sectional ◽

Death Rates ◽

First Trimester Of Pregnancy ◽

Tsh Levels

Objectives: The prime objective of this study was to evaluate and asses the prevalence and related complications of SCH in pregnant ladies in their 1st trimester of pregnancy in Pakistani population. Study Design: Cross Sectional study. Setting: Department of Medicine, Teaching Hospital, DG Khan, Pakistan. Period: 11th February 2017 to 29th December 2018. Material & Methods: We obtained informed consent from all patients. 457 pregnant ladies having last missed period till 12th week with age group between 18-45 years were included in this study. Samples were collected for T4 (Thyroxine), TSH (Thyroid Stimulating Hormone) and T3 (Triiodothyronine). Patients were followed for their entire pregnancy period. Adverse events and complications were noted. Results: Out of 457 patients who were included in our study, 169 subjects had TSH levels well above 4.6- 10 mIU/L. 288 subjects were having TSH levels below 4 mIU/L. The overall prevalence of subclinical hypothyroidism (SCH) was found to be 37% in pregnant women during their first trimester of pregnancy. Pregnant women having subclinical hypothyroidism (SCH) were having higher risks of loss of pregnancy, placental abruption and neonatal death rates as compared to euthyroid pregnant women. Conclusion: Our study concludes that overall prevalence of subclinical hypothyroidism (SCH) in Pakistani pregnant women during their first trimester of pregnancy was found to be 37%. Pregnant women having subclinical hypothyroidisms (SCH) were having higher risks of loss of pregnancy, placental abruption and neonatal death rates as compared to euthyroid pregnant women. In the light of these findings we recommend routine screening for TSH, free T3 and free T4 during pregnancy especially during 1st trimester of pregnancy.

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The Treatment of Hypothyroidism in Pregnancy

Romanian Journal of Diabetes Nutrition and Metabolic Diseases ◽

10.1515/rjdnmd-2017-0020 ◽

2017 ◽

Vol 24 (2) ◽

pp. 155-160

Author(s):

Rucsandra Dănciulescu Miulescu ◽

Andrada Doina Mihai

Keyword(s):

Pregnant Women ◽

Subclinical Hypothyroidism ◽

Thyroid Disease ◽

Hormone Deficiency ◽

Specific Reference ◽

Overt Hypothyroidism ◽

American Thyroid Association ◽

Diagnosis And Management ◽

Pregnancy And Postpartum ◽

In Pregnancy

Abstract Hypothyroidism is a pathologic condition generated by the thyroid hormone deficiency. The American Thyroid Association advises for the screening of hypothyroidism beginning at 35 years and thereafter every 5 years in people at high risk for this condition: females older than 60 years, pregnant women, patients with other autoimmune disease or patients with a history of neck irradiation. In pregnant women, hypothyroidism can been associated with adverse effect for both mother and child. The „Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum“ recommends the treatment of maternal overt hypothyroidism: females with a thyrotropin (TSH) level higher than the trimester-specific reference interval and decreased free thyroxine (FT4), and females for which TSH level is higher than 10.0 mIU/L, irrespective of the FT4 value, with administration of oral levothyroxine. The goal of treatment of maternal overt hypothyroidism is to bring back the serum TSH values to the reference range specific for the pregnancy trimester. The Guidelines of the „European Thyroid Association for the Management of Subclinical Hypothyroidism in Pregnancy and in Children“ recommends treatment of pregnancy associated subclinical hypothyroidism with the following levothyroxine doses: „1.20 μg/kg/day for TSH≤4.2 mU/l, 1.42 μg/kg/day for TSH >4.2-10 and 2.33 μg/kg/day for overt hypothyroidism“. The „Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum“ and the „European Thyroid Association for the Management of Subclinical Hypothyroidism in Pregnancy and in Children“ do not recommend the treatment of isolated hypothyroxinemia in pregnancy.

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Association of thyroid status with hemoglobin levels in pregnancy

International Journal of Research in Medical Sciences ◽

10.18203/2320-6012.ijrms20174936 ◽

2017 ◽

Vol 5 (11) ◽

pp. 4873 ◽

Cited By ~ 1

Author(s):

Manisha Baghel ◽

Jyoti Batra ◽

Thimmaraju K. V. ◽

Maliyanar Itagappa

Keyword(s):

Early Diagnosis ◽

Pregnant Women ◽

Thyroid Function ◽

First Trimester ◽

Thyroid Stimulating Hormone ◽

Obstetrics And Gynecology ◽

Thyroid Status ◽

Thyroid Profile ◽

Tsh Levels ◽

In Pregnancy

Background: The association of hemoglobin levels with thyroid status in pregnancy was not studied in detail. Therefore, in this study, we assessed the levels of hemoglobin, thyroid function and its association with hemoglobin levels in first trimester of pregnancy.Methods: Fifty pregnant women who didn’t start any supplementation were recruited from the obstetrics and gynecology outpatient department. Fifty age matched controls were recruited from the residents and staff of the hospital. Thyroid profile and hemoglobin levels were measured in both the groups. The association was seen between hemoglobin levels and thyroid stimulating hormone (TSH) levels.Results: The hemoglobin levels are significantly low in first trimester pregnant women. Further, the increased TSH levels are negatively correlated with low hemoglobin levels.Conclusions: Screening of hemoglobin levels in first trimester itself will be beneficial to prevent the complications of pregnancy. Further, hypothyroidism also present and associated with reduced hemoglobin. So, early diagnosis of these deficiencies will be useful to start giving supplements to avoid unwanted effects in pregnancy.

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Evaluation of Thyroid Function in Pregnant Women Using Automated Immunoassays

Clinical Chemistry ◽

10.1093/clinchem/hvab009 ◽

2021 ◽

Author(s):

K Aaron Geno ◽

Matthew S Reed ◽

Mark A Cervinski ◽

Robert D Nerenz

Keyword(s):

Pregnant Women ◽

Equilibrium Dialysis ◽

Reference Interval ◽

First Trimester ◽

Reference Intervals ◽

Free Thyroxine ◽

Specific Reference ◽

Childbearing Age ◽

Thyroid Autoantibody ◽

The Impact

Abstract Introduction Automated free thyroxine (FT4) immunoassays are widely available, but professional guidelines discourage their use in pregnant women due to theoretical under-recoveries attributed to increased thyroid hormone binding capacity and instead advocate the use of total T4 (TT4) or free thyroxine index (FTI). The impact of this recommendation on the classification of thyroid status in apparently euthyroid pregnant patients was evaluated. Methods After excluding specimens with thyroid autoantibody concentrations above reference limits, thyroid-stimulating hormone (TSH), FT4, TT4, and T-uptake were measured on the Roche Cobas® platform in remnant clinical specimens from at least 147 nonpregnant women of childbearing age and pregnant women at each trimester. Split-sample comparisons of FT4 as measured by the Cobas and equilibrium dialysis were performed. Results FT4 decreased with advancing gestational age by both immunoassay and equilibrium dialysis. TSH declined during the first trimester, remained constant in the second, and increased throughout the third, peaking just before delivery. Interpretation of TT4 concentrations using 1.5-times the nonpregnant reference interval classified 13.6% of first trimester specimens below the lower reference limit despite TSH concentrations within trimester-specific reference intervals. Five FTI results from 480 pregnant individuals (about 1.0%) fell outside the manufacturer’s reference interval. Conclusions Indirect FT4 immunoassay results interpreted in the context of trimester-specific reference intervals provide a practical and viable alternative to TT4 or FTI. Declining FT4 and increasing TSH concentrations near term suggest that declining FT4 is not an analytical artifact but represents a true physiological change in preparation for labor and delivery.

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