Thyroid Status In Pregnant Women Research Articles

Thyroid status in pregnant women with pregnancy induced hypertension – A case control study

Introduction: Pregnancy induced hypertension (PIH) is an important cause of maternal and fetal morbidity and mortality affecting 5-10% of pregnancies. PIH is more frequently associated with elevated TSH (Thyroid-stimulating hormone). Thyroid dysfunction plays an important role in the development of gestational hypertension. However, this relationship remains unclear. The study was performed to evaluate the thyroid status in pregnant women with PIH and normal pregnant women. Methodology: This was a hospital based observational case control study done in Dr M K Shah Medical College, Ahmedabad. Total 100 pregnant women were included, out of them 50 PIH women were included in the case study group and 50 normotensive healthy pregnant women were included in the control group. After taking written consent, thyroid profile (TSH, free T3 and free T4) were measured in all 100 subjects. Results: Women with PIH had higher TSH levels and lower free T3 and free T4 as compared to normotensive pregnant women. There was a significant association between hypothyroidism and PIH cases. There was a significant positive correlation between TSH and systolic BP (r=0.42) and diastolic BP (r=0.52). Conclusion: PIH women are at greater risk of decreased thyroid function. Therefore, PIH women should be monitored for thyroid levels regularly.

Selenium Supplementation in Pregnant Women with Autoimmune Thyroiditis: A Practical Approach.

Selenium (Se) is an essential trace element with antioxidant and anti-inflammatory properties and a pivotal role in thyroid metabolism. Ensuring a sufficient Se supply is possible via a balanced, wholesome diet; however, Se content in foods may be different throughout geographical areas. Se supplementation is expected to improve inflammatory status in patients with autoimmune thyroiditis, especially in those with high activity, and has been demonstrated as effective in reducing the thyroid peroxidase antibodies titer. Se status seems to affect thyroid function in pregnancy, which prompts the potential role of Se supplementation in such patients. Few clinical trials have investigated the effectiveness of Se supplementation in pregnant women with thyroiditis, and their results suggest the safety and effectiveness of this element in reducing autoantibody levels and preventing postpartum thyroiditis development, although limited. Hence, more robust evidence is needed to confirm these data. The current study aims to summarize published data on the relationship between Se and thyroid status in pregnant women with thyroiditis and the potential use of Se. Moreover, an algorithm for Se supplementation is proposed for pregnant women with thyroiditis to help endocrinologists in daily clinical practice to consider Se status.

Analysis of the thyroid status of pregnant women in the region of mild iodine deficiency

Introduction. Thyroid hormones play an important role during pregnancy, providing organogenesis, growth and development of the fetus, participate in the formation and development of the brain and its structures, affecting cognitive abilities. Thyroid dysfunction is associated with the pathological course of pregnancy and childbirth, as well as a negative effect on the fetus. Iodine deficiency, which persists throughout Russia, creates the preconditions for the more frequent development of subclinical hypothyroidism and hypothyroxinemia in pregnant women. Therefore, early detection of thyroid dysfunction during gestation in the region of iodine deficiency is relevant.Aim. To assess the thyroid status in pregnant women in the region of iodine deficiency.Materials and methods. A single-center, prospective, one-sample study was performed in a population of pregnant women registered from June 2019 to December 2019 to the antenatal clinic in Tyumen.Results. According to the results of biomedical monitoring of iodine deficiency in the population of pregnant women in Tyumen, iodine supply improved, as evidenced by the median concentration of ioduria 154.4 μg / l, the frequency of endemic goiter was 0.37%. Continuous screening of women in the 1st trimester of pregnancy without thyroid pathology revealed subclinical hypothyroidism in 21.5% of pregnant women, carriage of antibodies to thyroperoxidase was found in 10.5% of women.Conclusions. Given the persisting problem of iodine deficiency, the widespread occurrence of subclinical hypothyroidism in the population of pregnant women, it is necessary to include the study of thyroid status in the standard of examination of pregnant women when registering in an antenatal clinic for early diagnosis and timely treatment of hypothyroidism. It is also recommended to continue preventive measures aimed at replenishing the iodine deficiency starting from the stage of pregravid preparation.

Frequency and characteristics of thyroid dysfunction in pregnant women – screening of 547 women in Bulgaria

The Recommendations of the European Thyroid Association’2014 have been widespread among the medical community for many years. In them as well as in the latest Recommendations of the American Thyroid Association’2017 the first recommendation is related to the development of population-based reference limits based on data from the local population. The aim is to study the current functional thyroid status in pregnant Bulgarian women and to carefully assess in the light of modern understandings the specific diagnostic and therapeutic approach for our population. Material and Methods: The study was conducted as a cross-sectional multicenter population-based study, which included 547 pregnant women, mean age 30 ± 5 years. Fasting morning venous blood (TSH, FT4, TPOAb - determined by ECLIA method) and fresh morning urine sample (to determine urine iodine concentration) was taken, ultrasound examination of the thyroid gland was performed. Results: Based on the accepted cut-off for TSH according to the Recommendations of ETA’2014, the studied pregnant women were divided into six groups: Subclinical and Clinical hypothyroidism; Subclinical and Clinical hyperthyroidism; Euthyroid; Low T4 syndrome. Almost 2/3 of pregnant women have TSH < 2.5 mIU / L. Undiagnosed hypothyroidism is present in 121 pregnant women (22%), which is a bad feature of our health system. The data were analyzed in two TSH cut-offs (ETA’2014 and ATA’2017) and it was found that the increase in TSH cut-off for the first trimester did not change the absolute number of undiagnosed and untreated pregnant women with Clinical hypothyroidism, increasing 2.5 times its relative share, from 25.6% reaching 63.3% of all undiagnosed cases of hypothyroidism. Conclusion: Increasing the cut-off of TSH would unrealistically calm and neglect the follow-up of the pregnant women which is very dangerous. Efforts should focus on early screening for verbally identified risk factors. Of course, it is necessary to develop a national standard for TSH, which would serve more accurately to assess the thyroid status of pregnant women in the Bulgarian population.

Factors Determining Thyroid Status in Pregnant Women in Bulgaria

Thyroid dysfunction occurs in 5-18% of pregnant women and is associated with a higher risk of various gynecological and obstetric complications and these differences are due to the specific characteristic of the study population. The aim of the present study is to analyze the population of pregnant women in Bulgaria regarding the main parameters that are relevant to their thyroid status - age, sequence of pregnancy, reproductive problems, family history of thyroid disease, body mass index. Material: We studied 547 pregnant women, mean age 30±5 years. The study was conducted as a cross-sectional multicenter population-based in 10 regions of Bulgaria or a total of 84 settlements. Methods: An individual Questionnaire was completed, determined in a central laboratory with ECLIA method TSH, FT4, TPOAb and ultrasound examination of the cervical region was conducted. Statistical processing of the material was performed using the standard SPSS 13.0 for Windows. Results: TSH levels are negatively correlated with age, P<0.07. The thyroid volume for the group of women with first pregnancy (n-245, 44.8%) is 8.67±2.23 mL, median 8.35 mL, and the thyroid volume in the remaining 302 (55.2%) women with another pregnancy is 9.15±2.85 mL, median 8.96 mL (P<0.01). Reproductive problems were reported in 119 (21.8%) pregnant women, but the correlation with TSH levels was weak, P<0.009. In 25% of women with family history of thyroid pathology there are abnormalities in thyroid function (in 96.4% hypothyroidism and in 3.6% hyperthyroidism). While in euthyroid pregnant women previous obesity was present in 8.6% (30/350), in hypothyroid pregnant women it was found in 12.7% (14/110), P<0.035. In other words, BMI before pregnancy is a significant predictor of hypothyroidism, proven during pregnancy. Conclusion: The preliminary in-depth study and presentation of the characteristics of the studied Bulgarian population of pregnant women is the basis for a proper assessment of the condition of the thyroid gland.

Evaluation of Thyroid Function during Pregnancy: Have We Taken a Wrong Turn?

Recently, the American Thyroid Association (ATA)2 issued new guidelines for the diagnosis and management of thyroid diseases during pregnancy and the postpartum period (1). The document is an excellent review of current literature relating to the assessment of thyroid status during pregnancy. While universal screening for thyroid disease before or during pregnancy remains controversial, thyroid status can be accurately screened with thyroid-stimulating hormone (TSH), and additional testing such as free thyroxine (FT4) is required only when TSH is abnormal. However, one of the recommendations of the ATA document stood out: Recommendation 3 reads, “Accurate estimation of the FT4 concentrations can also be done by calculating a FT4 index.” The FT4 index is a virtually obsolete estimation of FT4 that has been replaced by newer and more accurate FT4 immunoassays and LC-MS/MS. This recommendation is based on the panel's observation that “Current uncertainty around FT4 estimates in pregnancy has led some to question the wisdom of relying on any FT4 immunoassays during pregnancy.” Here I would like to review the source of this uncertainty and propose an alternative interpretation of the literature. ### SOURCES OF UNCERTAINTY In 1991, Roti et al. compared 10 different radioimmunoassay methods for free triiodothyronine (FT3) and FT4 (2). They observed that whereas FT4 concentrations were often lower in pregnant (third trimester) women than nonpregnant women, the TSH concentrations remained within the reference interval. These findings suggested that many of the assays available at that time for the measurement of serum free thyroid hormone concentrations did not seem adequate to evaluate the real thyroid status of pregnant women. Indeed, since then numerous studies have demonstrated that FT4 measured by …

Thyroid Function in Pregnant Women from a West-African Population

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.

Effect of Thiocyanate on Iodine Status of Pregnant Women.

The aim of this study was to assess the thyroid status of pregnant women on the basis of biochemical indicators and to evaluate the potential risk of developing iodine deficiency as a result of tobacco smoke exposure by assessing the association between urinary thiocyanate levels and the manifestation of iodine deficiency. The study included 219 pregnant women from the town of Plovdiv and Plovdiv District in Southern Bulgaria. The levels of urinary iodine, thyroid-stimulating hormone (TSH), free thyroxine (FT4), and urinary thiocyanate as indicators of tobacco smoke exposure were measured. Most of the pregnant women (60.1%) were found to have iodine deficiency, 10.6% of them had TSH values greater than 4mIU/L, and 16.4% had FT4 below 9pmol/L. There were negative correlations between urinary iodine levels and thiocyanate/creatinine ratio (R = -0.148, р = 0.034) and between thiocyanate/creatinine ratio and FT4 (R = -0.379, p < 0.0001); thiocyanate/creatinine ratio and serum TSH were positively correlated (R = 0.169, p = 0.019). Logistic regression analysis showed that pregnant women in whom the thiocyanate/creatinine ratio was greater than the median value of 3.57mg/g had a 3.882-fold higher risk of developing iodine deficiency (urinary iodine <150μg/L) than the pregnant women with lower thiocyanate levels (OR = 3.882, 95% CI 1.402-10.751, p = 0.009). Higher levels of urinary thiocyanate were found in women exposed to tobacco smoke, and quantification of these ions in urine provided a fast non-invasive method to monitor thiocyanate load. Due to the competitive inhibition of iodine intake by thiocyanates, their levels should be carefully monitored, especially in cases of severe iodine deficiency.

Thyroid status in pregnant women and association with nitrates as an environmental factor stimulating the manifestation of iodine deficiency

Thyroid status in pregnant women and association with nitrates as an environmental factor stimulating the manifestation of iodine deficiency

Thyroid status of the pregnant women of Manipur: A comparison of American Thyroid Association guidelines and normal laboratory reference range

Gestation is the period when the thyroid function parameters undergo several changes. As the range of thyroid hormone levels differ in the gestational period due to the various physiological changes, the hormonal range, which is used for the normal population cannot be used for pregnant women. Our study was done to find the thyroid status of pregnant women by comparing the trimester specific range as published by American Thyroid Association (ATA) guidelines with the normal population/laboratory reference range. A total of 377 patients with a distribution of 110,149 and 118 among the trimesters were studied. One patient each in first and second trimester had overt hypothyroidism when trimester specific reference range as published by ATA was followed. The prevalence of subclinical hypothyroidism as per ATA guidelines were 34.4, 31.5 and 30.5%, in the respective trimesters. The prevalence of subclinical hypothyroidism on taking into account the normal laboratory reference range of 3.6, 2.6 and 6.8% in the respective trimesters. Overt hypothyroidism was seen, one each in the first and second trimester and 29.3% were misdiagnosed as normal patients in this study. It is inferred that large number of patients will be misdiagnosed as having normal thyroid function during pregnancy if the trimester specific reference range is not followed. Thus we conclude that the pregnancy reference range should be used to interpret the thyroid hormones in pregnancy to avoid the misdiagnosis, as thyroid hormones are necessary for the normal fetal brain development.

Longitudinal evaluation of thyroid autoimmunity and function in pregnant Korean women

Maternal thyroid dysfunction during pregnancy has been associated with adverse outcomes for both the mother and child. For this reason, it is important to understand thyroid status in pregnant women. However, there are relatively few published studies that examine thyroid function tests (TFT) and thyroid autoimmunity in non-Western pregnant women. Serum samples were longitudinally collected throughout pregnancy from 108 Korean women. TFT, thyroid peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (Tg-Ab) testing was performed. The impact of gestational age on TPO-Ab and Tg-Ab levels was evaluated and gestational age-specific reference intervals for TFT were established in antibody negative women. In the first trimester, TPO-Ab and Tg-Ab were positive in 13.9% and 16.7% of women, respectively. For antibody positive women, median autoantibody levels for TPO-Ab and Tg-Ab dropped from first trimester to near term (133.7-10.5 IU/mL, and 162.1-21.9 IU/mL, respectively). Antibody status influenced thyroid stimulating hormone (TSH) during the first trimester, and TSH, free T4 (FT4) and total T4 (TT4) in the early second trimester. Later in gestation, no significant differences in TFT were found based on antibody status. Gestational age-specific reference intervals for TFT were calculated in antibody negative women. Laboratory evidence of autoimmune thyroid disease (AITD) is common in this population of pregnant Korean women. Antibody status influences TFT values in the first and early second trimester. Thyroid autoantibody status and titer change in an individual-specific manner throughout pregnancy. Gestational age-specific reference intervals should be utilized for interpretation of TFT results in pregnant women.

The Influence of Selenium Supplementation on Postpartum Thyroid Status in Pregnant Women with Thyroid Peroxidase Autoantibodies

Pregnant women who are positive for thyroid peroxidase antibodies [TPOAb(+)] are prone to develop postpartum thyroid dysfunction (PPTD) and permanent hypothyroidism. Selenium (Se) decreases thyroid inflammatory activity in patients with autoimmune thyroiditis. We examined whether Se supplementation, during and after pregnancy, influences the thyroidal autoimmune pattern and function. This was a prospective, randomized, placebo-controlled study. The study was conducted in the Department of Obstetrics and Gynecology and Department of Endocrinology. A total of 2143 euthyroid pregnant women participated in the study; 7.9% were TPOAb(+). During pregnancy and the postpartum period, 77 TPOAb(+) women received selenomethionine 200 microg/d (group S1), 74 TPOAb(+) women received placebo (group S0), and 81 TPOAb(-) age-matched women were the control group (group C). We measured the prevalence of PPTD and hypothyroidism. PPTD and permanent hypothyroidism were significantly lower in group S1 compared with S0 (28.6 vs. 48.6%, P<0.01; and 11.7 vs. 20.3%, P<0.01). Se supplementation during pregnancy and in the postpartum period reduced thyroid inflammatory activity and the incidence of hypothyroidism.

Maternal hypothyroxinaemia during the first half of gestation in an iodine deficient area with endemic cretinism and related disorders

Iodine deficiency is well known as the cause of several disorders such as endemic goitre and cretinism, along with a wide spectrum of psychoneurological development disorders including endemic mental deficiency and endemic cognitive deficiency, which are generally correlated to damage to the fetus. Such damage is, by inference, deemed a consequence either directly of iodine deficiency or of insufficient availability of thyroxine at the feto-placental unit level. Early pregnancy represents the crucial period for neurogenesis in the embryo. Several experimental studies have emphasized the direct role of maternal T4 in neurological embryogenesis, before the onset of fetal thyroid function and, therefore, its protective role in fetal thyroid failure. The objective of this study was to evaluate whether iodine deficiency may influence thyroid status of pregnant women throughout the first half of pregnancy. Thyroid function tests including total and free T4 and T3, TBG and TSH along with urinary iodine excretion were measured in the serum of pregnant women from an iodine deficient endemic goitre area in north-eastern Sicily, at 8, 13 and 20 weeks of gestation. The times of sampling were chosen to correspond approximately to a period prior to, coincident with and after the onset of fetal thyroid function, respectively. The longitudinal study was undertaken in 16 euthyroid pregnant women from the iodine deficient area in which major iodine deficiency disorders such as endemic cretinism and endemic cognitive deficiency in schoolchildren still persist (area A) and in 7 age matched volunteer pregnant women from a marginally iodine sufficient area (area B). Hormones and TBG were measured using commercial kits. Urinary iodine was measured by an automated method. The divergent changes in serum T4 and TBG with pregnancy progression induced a progressive TBG desaturation by T4 during the whole study period (from 22 to 17% in area A, ANOVA two-way F = 18.9, P < 0.0001; from 33 to 20% in area B, F = 20.7, P < 0.0005) in both areas. At 20 weeks, average FT4 levels were lower in area A than in area B (11.5 +/- 2.5 vs 14.3 +/- 2.4 pmol/l, t = 2.7 P < 0.01) and were below the normal range in 2/16 and borderline-low in 6/16 pregnant women. FT4 serum levels were inversely related to TSH concentrations (r = -0.54, P < 0.0001) which progressively increased, in area A, during the whole study period (F = 6.0, P < 0.01) and were abnormally high in the two women with low FT4, but not in area B. Also in area A (F = 3.4, P < 0.05) a significant T3/T4 molar ratio increase was observed. Iodine deficiency induces in early pregnancy a series of events (reduced synthesis of maternal T4, TBG desaturation by T4, critical decrease of FT4 levels with consequent TSH increase) responsible for overt or marginal biochemical hypothyroidism in about 50% of pregnant women. It is hypothesized that the imbalance of maternal thyroid hormone homeostasis during pregnancy as a consequence of endemic iodine deficiency may be responsible for the impaired psychoneurological development observed in children from that area so appropriate iodine and/or thyroxine prophylaxis to women in that region may prevent the neurobehavioural, cognitive and motor compromise of the population.

The thyroid in anemic pregnant women under conditions of endemic goiter

Anemia is a highly prevalent condition among pregnant women in the Republic of Kazakhstan. The causes of this anemia are not quite clear, as is the problem of resistance of this type of anemia to therapy with iron preparations. The authors propose that this may be explained by the fact that many regions of the Republic are foci of endemic goiter, because tentative studies indicate a relationship between endemic goiter and hy- pothyrosis. The present study was aimed at examination of the thyroid status in pregnant women suffering from anemia in the town of Alma-Ata, a region endemic for goiter. Altogether 120 anemic pregnant women were examined, 60 of these with goiter and 60 without it. Control group consisted of 20 healthy pregnant women. Clinical and ultrasonic examinations, puncture biopsy of the thyroid, measurements of blood levels of TTH, total and free triiodothyronine and thyroxin, thyroxin-binding globulin, as well as of peripheral blood red cell counts, levels of hemoglobin, serum iron, assessment of total iron-binding capacity of the serum and saturation coefficient, were carried out. Healthy pregnant women from a focus of endemic goiter were found to represent a group at risk of anemia in the third pregnancy trimester. In anemic pregnant women endemic goiter aggravated anemia. Chronic iodine deficiency is conductive to formation in pregnant women of subclinical hypothyrosis whose severity increased in the presence of anemia, more so if anemia is paralleled by goiter.

Changes in thyroid status in pregnant women treated with ritodrine

In a clinical study of 17 pregnant women treated with ritodrine, a β 2-sympathomimetic agent used for tocolysis, thyroid hormone status was assessed longitudinally. This was done in order to verify the hypothesis that an increase in T 3 levels could result from adrenergic stimulation, since propranolol, a beta blocking agent, has proved to decrease T 3 levels in man. Indeed, a statistically significant increase in T 3 serum concentration and in T 3 T 4 ratio was found on the second day after the start of treatment with ritodrine (p < 0.02 and < 0.01 respectively). After discontinuation of treatment a decrease in T 3 serum levels, compared to both treatment and pretreatment levels, was observed. The free T 4 concentration showed a significant drop after the first week of treatment (p < 0.01), but no changes were found in T 4 and TSH levels. It was concluded that the β 2-mimetic-mediated changes in thyroid status provide one more reason for restriction of the use of β-mimetic drugs in hyperthyroidic patients and might offer an additional explanation for the undesirable chronotropic cardiac side-effects of the therapy.

Assessment of thyroid status in pregnant women and in patients taking oral contraceptives by a free thyroxine index.

The results of using a product of serum thyroxine and triiodothyronine binding coefficient, estimated by simple methods, to give a ;free thyroxine index' in normal women, in pregnant women, and in patients taking oral contraceptives is described. The method is believed to provide a reliable means of assessing thyroid status, and very close agreement, with no significant difference between the mean values obtained for the free thyroxine index, was found in the groups studied. Certain changes, which may be significant, in the values obtained in patients on oral contraceptive treatment of varying duration were noted.