scholarly journals Thyroid size and thyroid function during pregnancy: an analysis

1998 ◽  
pp. 536-542 ◽  
Author(s):  
A Berghout ◽  
W Wiersinga

An analysis of all available studies of thyroid size and function in pregnancy reveals that thyroid size, estimated by inspection and palpation or measured more accurately by ultrasonography, increases in pregnancy in areas of iodine deficiency but not in those with sufficient iodine. The increase in average thyroid size is within the normal range, and can partly be prevented by treatment with extra iodine or thyroxine. There is a slight transient increase in free thyroxine in the first trimester, probably as a result of physiological stimulation of thyroid function by human choriogonadotrophin. These levels then decrease by about 30% to low normal values in the second and third trimesters of pregnancy in both iodine-depleted and -replete areas. These changes resemble those of non-thyroidal illness and may well play a role in reducing energy expenditure during pregnancy. The increase in thyroid size in iodine-deficient areas is probably due to autoregulatory mechanisms of iodine on thyroid growth. The hypothesis is supported by the fact that, during pregnancy, thyroid volume and thyroid function adapt in a physiological way to meet the increased demands for iodine and energy.

2016 ◽  
Vol 9 (3) ◽  
pp. 126-129 ◽  
Author(s):  
Helen Robinson ◽  
Philip Robinson ◽  
Michael D’Emden ◽  
Kassam Mahomed

Background First-trimester care of maternal thyroid dysfunction has previously been shown to be poor. This study evaluates early management of thyroid dysfunction in pregnancy in Australia. Methods Patients reviewed by the Obstetric Medicine team for thyroid dysfunction from 1 January 2012 to 30 June 2013 were included. Data were collected on gestation at referral from the patient’s general practitioner to the antenatal clinic, information provided in the referral letter, thyroid function tests and thyroid medications. Results Eighty-five women were included in the study. At the time of general practitioner referral to antenatal services, 19% of women with preexisting thyroid disease had no thyroid function tested. Forty-three percent had an abnormal thyroid-stimulating hormone defined as being outside the laboratory-specific pregnancy reference range if available, or outside the level of 0.1–2.5 mIu/L in the first trimester, 0.2–3.0 mIu/L in the second trimester and 0.3–3.0 mIu/L in the third trimester. Only 21% of women increased their thyroxine dose prior to their first antenatal clinic review. Conclusion This study highlights that a significant proportion of women with known thyroid disease either have untested thyroid function in the first trimester or a thyroid-stimulating hormone outside of levels recommended by guidelines.


2018 ◽  
Vol 19 (2) ◽  
pp. 98
Author(s):  
Mohammad Saifur Rahman ◽  
Sadia Sultana ◽  
Ayesha Nazneen

<p><strong>Objectives:  </strong>Thyroid disorders are commonly observed in pregnancy. Thyroid hormones play an important role in embryogenesis and fetal development. The fetus is completely dependent on the mother for thyroid hormone in first trimester. About 10% of all pregnant women can be affected by thyroid disorders during pregnancy. Thyroid function abnormalities in pregnancy are a challenge for the concerned physicians.  The objective of this study was to assess the maternal thyroid function in first trimester of pregnancy.</p><p><strong>Patients and Methods: </strong>A descriptive cross sectional study was carried out at the Combined Military Hospital (CMH), Dhaka over a period of one year from January 2013 to December 2013 to see the serum FT<sub>3</sub>, FT<sub>4</sub>, TSH, thyroid antibodies level and common thyroid disorders in pregnancy. A total of 138 pregnant women in their first trimester (up to 12 weeks) of pregnancy with an age range of 18-35 years were enrolled in this study. Pregnant women with known thyroid disorder and on treatment and pregnancy more than three months were excluded. Measurement of serum FT<sub>3</sub>, FT<sub>4</sub>, TSH, Anti TPO-Ab and Anti TG-Ab were done in each patient at the time of enrolment. Ultrasonography of each patient was done for confirmation of pregnancy and correlation of gestational age.</p><p><strong>Results:  </strong>Among 138 pregnant women, subclinical hypothyroidism was detected in 10 (7.2%) patients and subclinical hyperthyroidism was detected in 3 (2.2%) patients. Mean difference of the investigation findings were not statistically significant among primi and multi gravida. TPO-Ab and TG-Ab difference were statistically significant between two age groups.</p><p><strong>Conclusion: </strong>Subclinical thyroid disorders are fairly high among pregnant women. Correct diagnosis in early pregnancy and prompt treatment will bring an excellent prognosis for both mother and offspring.</p><p>Bangladesh J. Nuclear Med. 19(2): 98-102, July 2016</p>


2020 ◽  
Vol 11 ◽  
Author(s):  
Tal Schiller ◽  
Arnon Agmon ◽  
Viviana Ostrovsky ◽  
Gabi Shefer ◽  
Hilla Knobler ◽  
...  

IntroductionAn Israeli national survey found that 85% of pregnant women had urinary iodine content (UIC) levels below the adequacy range (&lt;150 µg/L). Widespread desalinated water usage and no national fortification plan are possible causes. Studies assessing relationships between iodine status and maternal and neonatal thyroid function provided varying results. Our aims were to determine whether iodine deficiency was associated with altered maternal or neonatal thyroid function and the factors leading to iodine deficiency.MethodsA cross-sectional study including 100 healthy women without prior thyroid disease, in their first trimester of a singleton pregnancy were recruited from an HMO clinic in central Israel. The women were followed from their first trimester. All women completed a 24-h dietary recall and life habits questionnaires. We tested for UIC, maternal and neonatal thyroid function, maternal autoantibodies, and neonatal outcomes.ResultsMedian UIC in our cohort was 49 µg/L [25%–75% interquartile range (IQR) 16-91.5 µg/L], with 84% below adequacy range. No correlation was found between iodine deficiency and maternal or neonatal thyroid function which remained within normal ranges. Antibody status did not differ, but thyroglobulin levels were significantly higher in iodine insufficient subjects. UIC was higher in women consuming an iodine containing supplement. There was no association between UIC and dietary iodine content or water source.ConclusionsModerate iodine deficiency is common in our healthy pregnant women population. Our data imply that moderate iodine deficiency in pregnancy seem sufficient to maintain normal maternal and neonatal thyroid function.


1966 ◽  
Vol 12 (9) ◽  
pp. 577-585 ◽  
Author(s):  
Derek Watson

Abstract Successful laboratory tests for early pregnancy utilize the endogenous production and excretion of chorionic gonadotrophin (CG). There is wide variation in sensitivity and specificity of various biological and commercially available immunochemical methods for determining urinary CG levels. Normal values for immunochemically reactive CG during the first trimester of pregnancy are given. Serial determinations of CG have diagnostic value in assessing various abnormal pregnancy states. An abnormally increased urinary output of CG is observed in some neoplasms—e.g., chorionepithelioma, and a rapidly rising CG level is strongly suggestive of molar pregnancy. Urinary CG levels falling below the normal range mayindicate an ectopic pregnancy or an inevitable, incomplete, or "missed" abortion. The immunochemical CG determination also offers a sensitive, simple, and convenient routine method for following patients who have been treated for hydatidiformmole or chorionepithelioma.


2015 ◽  
Vol 173 (4) ◽  
pp. 417-424 ◽  
Author(s):  
Andrea Busnelli ◽  
Guia Vannucchi ◽  
Alessio Paffoni ◽  
Sonia Faulisi ◽  
Laura Fugazzola ◽  
...  

ObjectiveAbout one out of two women with primary hypothyroidism has to increase the dosage of exogenous levothyroxine (l-T4) during pregnancy. Considering the detrimental impact of IVF on thyroid function, it has been claimed but not demonstrated thatl-T4dose adjustment may be more significant in hypothyroid women who become pregnant after IVF.DesignRetrospective cohort study.MethodsHypothyroid-treated women who achieved a live birth through IVF were reviewed. Women could be included if thyroid function was well compensated withl-T4before the IVF cycle (i.e., serum TSH <2.5 mIU/l and serum free T4within the normal range). Serum TSH and dose adjustment were evaluated at five time points during pregnancy. The trimester ranges for serum TSH considered as reference to adjustl-T4therapy were 0.1–2.5 mIU/l for the first trimester, 0.2–3.0 mIU/l for the second trimester, and 0.3–3.0 mIU/l for the third trimester.ResultsThirty-eight women were selected. During the whole pregnancy 32 women (84%; 95% CI: 72–96%) required an increase in the dose ofl-T4. In most cases (n=28), this occured within the first 5–7 weeks of gestation (74%, 95% CI: 58–85%). At 5–7 weeks of gestation, the median (interquartile range) increase ofl-T4dose for the whole cohort was 26% (0–50%). At 30–32 weeks, it was 33% (14–68%). In order to identify predictive factors of dose adjustment, we compared women who did (n=28) and did not (n=10) adjustl-T4dosage at 5–7 weeks' gestation. Significant differences emerged for thyroid autoimmunity prevalence and for the distribution of hypothyroidism aetiology.ConclusionsThe vast majority of hypothyroid-treated women who achieve pregnancy through IVF need an increase in thel-T4dose during gestation. This requirement tends to occur very early during gestation.


2017 ◽  
Vol 1 (3) ◽  
pp. 01-04
Author(s):  
R F Gross man

Pregnancy has a profound impact on the thyroid gland and thyroid function since the thyroid may encounter changes to hormones and size during pregnancy. The diagnosis and treatment of thyroid disease during pregnancy and the postpartum is complex but knowledge regarding the interaction between the thyroids and pregnancy/the postpartum period is advancing at a rapid pace. For women known to have hypothyroidism, an increase in thyroxine dose by 20–40% when pregnancy is confirmed usually ensures they remain euthyroid. Treatment of subclinical hypothyroidism is recommended if the woman has antithyroid antibodies. Treatment of hyperthyroidism, unless it is related to human chorionic gonadotrophin, involves propylthiouracil in the first trimester. Carbimazole may be used in the second trimester. Thyroid function tests are checked every month and every two weeks following a change in dose. Women with a current or a past history of Graves’ disease who have thyrotropin receptor antibodies require early specialist referral as there is a 1–5% risk of fetal hyperthyroidism. Women with thyroid disorders in pregnancy should be followed up by their GP in the postpartum period. Postpartum thyroiditis may present months after delivery.


2017 ◽  
Vol 102 (7) ◽  
pp. 2533-2542 ◽  
Author(s):  
Mary H. Samuels ◽  
Irina Kolobova ◽  
Megan Antosik ◽  
Meike Niederhausen ◽  
Jonathan Q. Purnell ◽  
...  

Abstract Purpose: It is not clear whether upper limits of the thyrotropin (TSH) reference range should be lowered. This debate can be better informed by investigation of whether variations in thyroid function within the reference range have clinical effects. Thyroid hormone plays a critical role in determining energy expenditure, body mass, and body composition, and therefore clinically relevant variations in these parameters may occur across the normal range of thyroid function. Methods: This was a cross-sectional study of 140 otherwise healthy hypothyroid subjects receiving chronic replacement therapy with levothyroxine (L-T4) who had TSH levels across the full span of the laboratory reference range (0.34 to 5.6 mU/L). Subjects underwent detailed tests of energy expenditure (total and resting energy expenditure, thermic effect of food, physical activity energy expenditure), substrate oxidation, diet intake, and body composition. Results: Subjects with low-normal (≤2.5 mU/L) and high-normal (&gt;2.5 mU/L) TSH levels did not differ in any of the outcome measures. However, across the entire group, serum free triiodothyronine (fT3) levels were directly correlated with resting energy expenditure, body mass index (BMI), body fat mass, and visceral fat mass, with clinically relevant variations in these outcomes. Conclusions: Variations in thyroid function within the laboratory reference range have clinically relevant correlations with resting energy expenditure, BMI, and body composition in L-T4–treated subjects. However, salutary effects of higher fT3 levels on energy expenditure may be counteracted by deleterious effects on body weight and composition. Further studies are needed before these outcomes should be used as a basis for altering L-T4 doses in L-T4–treated subjects.


2020 ◽  
Vol 76 (3) ◽  
pp. 165-174
Author(s):  
Wenxing Guo ◽  
Wei Wang ◽  
Ya Jin ◽  
Wen Chen ◽  
Lu Chen ◽  
...  

Objectives: To explore trimester-specific thyroid function changes under different iodine statuses throughout pregnancy. Methods: A cross-sectional study was conducted to assess the pregnancy iodine status, and 2,378 healthy pregnant women covering all 3 trimesters were recruited. Urinary iodine concentration (UIC) was measured by collecting spot urine samples. Blood samples were collected to evaluate thyroid function. Thyroid B-ultrasonography was conducted to measure the thyroid volume (Tvol). Results: The median UIC was 168 μg/L (111–263 μg/L). The UIC, free triiodothyronine (FT3), and free thyroxine (FT4) were significantly decreased as the pregnancy progressed (p < 0.001, p for trend <0.001), while Tvol increased (p < 0.001, p for trend <0.001). Thyrotropin (TSH) was significantly different between the 3 trimesters and showed an upward trend (p < 0.001), but the p for trend was not significant (p for trend = 0.88). After stratification by UIC, there were no significant differences in serum TSH, FT4, or FT3 level between UIC groups. Tvol was significantly higher in the UIC ≥500 μg/L group in the first trimester (β: 2.41, 95% CI: 1.09–3.72, p <0.001), as well as in the 250 ≤ UIC < 500 μg/L group (β: 1.65, 95% CI: 0.61–2.70, p < 0.001) and UIC ≥500 μg/L group (β: 3.35, 95% CI: 1.96–4.74, p < 0.001) in the third trimester. Conclusions: No difference was observed in TSH, FT3, or FT4 among the different iodine status groups throughout pregnancy. Tvol increased as the pregnancy progressed, and it was especially higher in the UIC ≥500 μg/L group in the first and third trimesters.


1986 ◽  
Vol 32 (5) ◽  
pp. 808-810 ◽  
Author(s):  
M Schöneshöfer ◽  
B Weber ◽  
W Oelkers ◽  
K Nahoul ◽  
F Mantero

Abstract Using liquid chromatography, we estimated the urinary excretion of 20 alpha-dihydrocortisol (20-DH) and urinary free cortisol (UFC) in normal subjects and in 40 patients with Cushing's syndrome of different etiologies. The median normal excretion rate (nmol/24 h) was 174 for 20-DH and 68 for UFC, the 20-DH/UFC ratio thus being 2.55. For patients with Cushing's syndrome, the excretion rate was 1798 for 20-DH and 298 for UFC, the ratio 6.03. We evaluated the effect of acute stimulation of adrenal secretion on 20-DH and UFC by administering corticotropin to six normal subjects. After such stimulation, the excretion rate was 566 for 20-DH and 1238 for UFC (ratio 0.45). Whereas 20-DH excretion rate exceeded the normal range in all patients, six patients had normal or even below-normal values for UFC excretion. Evidently, measurement of urinary 20-DH is a better test for chronic hypercorticoidism than is measurement of urinary UFC, and chronic hypercorticoidism can be differentiated from the acute state by the 20-DH/UFC ratio.


2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A837-A837
Author(s):  
Stephanie Behringer-Massera ◽  
Syed A Morshed ◽  
Terry F Davies

Abstract In women who are pregnant, the presence of thyroid autoantibodies is associated with an increased rate of miscarriage in the first trimester, with multiple reports averaging ~17% compared with ~8% in autoantibody negative women. During pregnancy immune tolerance is altered to allow implantation of the semi-allogeneic fetus and T-regulatory cells (Tregs), which play a major role in such tolerance, have been shown to increase during pregnancy, reaching a peak in the second trimester. A deficiency in this Treg response has been widely associated with spontaneous miscarriages. While it is known that the number of Tregs in patients with autoimmune thyroid disease (AITD) is decreased there are no data on pregnant women with AITD. In this study, we examined both the number and function of Tregs in pregnant women with (n=26) and without (n=41) thyroid autoantibodies (anti-Tg and/or anti-TPO) as well as healthy non pregnant women (n=25). Tregs were measured by flow cytometry of isolated CD4+, CD25+ and FoxP3+ T-cells. We found that the total number of CD4+CD25+FoxP3+ high Tregs was significantly increased in pregnancy consistent with previous reports (from 11% to 22%, p&lt;0.024). Furthermore, this increase in Tregs was less in pregnant women with thyroid autoantibodies (mean of 12%). In addition, studies of phosphorylated signal transducer and activator of transcription-5a (pStat-5a) as a marker of Treg function, showed that while Tregs were activated in pregnancy, their activity per cell was diminished in the pregnant antibody positive women with a frequency:MFI ratio of 201 compared to 316 in the negative group. These data demonstrate that pregnant women with thyroid antibodies have a reduced Treg response to pregnancy, both in number and function, and offer a likely explanation for the increased miscarriage rate in such patients.


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