| Peer-Reviewed

Factors Determining Thyroid Status in Pregnant Women in Bulgaria

Received: 23 November 2020    Accepted: 8 December 2020    Published: 31 December 2020
Views:       Downloads:
Abstract

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.

Published in International Journal of Diabetes and Endocrinology (Volume 5, Issue 4)
DOI 10.11648/j.ijde.20200504.17
Page(s) 89-95
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Thyroid Status, Age, Sequence of Pregnancy, Reproductive Problems, Family History, Body Mass Index

References
[1] Valdes S, Maldonado-Araque C, Lago-Sampedro A, Lillo JA, Garcia-Fuentes E, Perez-Valero V, et al. (2017). Population-Based National Prevalence of Thyroid Dysfunction in Spain and Associated Factors: Di@bet.es Study. Thyroid. 27 (2): 156-66.
[2] Lazarus J, Brown RS, Daumerie C, Hubalewska-Dydejczyk A, Negro R, Vaidya B. (2014). 2014 European thyroid association guidelines for the management of subclinical hypothyroidism in pregnancy and in children. Eur Thyroid J. 3 (2): 76–94.
[3] De Groot L, Abalovich M, Alexander EK, Amino N, Barbour L, Cobin RH, Eastman CJ, Lazarus JH, Luton D, Mandel SJ, Mestman J, Rovet J, Sullivan S. (2012). Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 97 (8): 2543–2565.
[4] Stagnaro-Green A, Abalovich M, Alexander E, Azizi F, Mestman J, Negro R, Nixon A, Pearce EN, Soldin OP, Sullivan S, Wiersinga W. (2011). American Thyroid Association Taskforce on Thyroid Disease During Pregnancy and Postpartum. Guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and postpartum. Thyroid 21 (10): 1081-1125.
[5] Chan S, Boelaert K. (2015). Optimal management of hypothyroidism, hypothyroxinaemia and euthyroid TPO antibody positivity preconception and in pregnancy. Clin Endocrinol (Oxf). 82 (3): 313–326.
[6] Taylor PN, Muller I, Nana M, Velasco I, Lazarus JH. Indications for treatment of subclinical hypothyroidism and isolated hypothyroxinaemia in pregnancy. (2020). Best Pract Res Clin Endocrinol Metab. 34 (4): 101436. doi: 10.1016/j.beem.2020.101436.
[7] Abalovich M, Alcaraz G, Kleiman-Rubinsztein J, Pavlove MM, Cornelio C, Levalle O, Gutierrez S. (2010). The relationship of preconception thyrotropin levels to requirements for increasing the levothyroxine dose during pregnancy in women with primary hypothyroidism. Thyroid 20: 1175–1178.
[8] Lazarus JH. (2011). Thyroid function in pregnancy. Br Med Bull 97: 137–148.
[9] Moreno-Reyes R, Glinoer D, Van Oyen H, Vandevijvere S. (2013). High prevalence of thyroid disorders in pregnant women in a mildly iodine-deficient country: a population-based study. J Clin Endocrinol Metab 98: 3694–3701.
[10] Aguayo A, Grau G, Vela A, Aniel-Quiroga A, Espada M, Martul P, Castaño L, Rica IJ. (2013). Urinary iodine and thyroid function in a population of healthy pregnant women in the North of Spain. Trace Elem Med Biol 27: 302–306.
[11] Alkafajei A, Amarin Z, Alazaizeh W, Khader Y, Marji M. (2012). Prevalence and risk factors for hypothyroidism in Jordanian women: comparison between different reference ranges. East Med Health J 18: 2.
[12] Мedici M, de Rijke YB, Peeters RP, Visser W, de Muinck Keizer-Schrama SM, Jaddoe VV, Hofman A, Hooijkaas H, Steegers EA, Tiemeier H. (2012). Maternal early pregnancy and newborn thyroid hormone parameters: the generation R study. J Clin Endocrinol Metab. 97 (2): 646–652.
[13] Li C, Shan Z, Mao J, Wang W, Xie X, Zhou W, Li C, Xu B, Bi L, Meng T, Du J, Zhang S, Gao Z, Zhang X, Yang L, Fan C, Teng W. (2014). 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? J Clin Endocrinol Metab. 99 (1): 73-79.
[14] Marx H, Amin P, Lazarus JH. (2008). Hyperthyroidism and pregnancy. BMJ 336: 663-667.
[15] Weiwei Wang, Weiping Teng, Zhongyan Shan, Sen Wang, Jianxin Li, Lin Zhu, Jin Zhou, Jinyuan Mao, Xiaohui Yu, Jia Li, Yanyan Chen, Haibo Xue, Chenling Fan, Hong Wang, Hongmei Zhang, Chenyang Li, Weiwei Zhou, Bo Gao, Tao Shang, Jiaren Zhou, Bin Ding, Ying Ma, Ying Wu, Hui Xu, Wei Liu. (2011). The prevalence of thyroid disorders during early pregnancy in China: the benefits of universal screening in the first trimester of pregnancy. Eur J Endocrinol 164: 263-268.
[16] World Medical Association (2013). "Declaration of Helsinki: Ethical Principles for Medical Research Involving Human Subjects". JAMA. 310 (20): 2191–2194. doi: 10.1001/jama.2013.28105.
[17] Brunn J, Block U, Ruf G, Bos I, Kunze WP, Scriba PC. (1981). Volumetric analysis of thyroid lobes by real-time ultrasound. Dtsch Med Wochenschr. 106: 1338–1340.
[18] Zimmermann MB, Hess S. Y, de Benoist L. M. B, Delange F, Braverman L. E, Fujieda K, Ito Y, Jooste P. L, Moos K, Jooste P. L, Pearce E. N, Pretell E. A, Shishiba Y.(2004). New reference values for thyroid volume by ultrasound in iodine sufficient school children: a World Health Organization/Nutrition for Health and Development Iodine Deficiency Study Group Report. Am J Clin Nutr 79: 231–237.
[19] Korevaar T. I. M, Medici M, Visser TJ, Peeters RP. (2017). Thyroid disease in pregnancy: new insights in diagnosis and clinical management. Nat Rev Endocrinol. 13 (10): 610-622.
[20] Negro R. (2019). Levothyroxine before conception in women with thyroid antibodies: a step forward in the management of thyroid disease in pregnancy. Thyroid Research 12: 5. https://doi.org/10.1186/s13044-019-0066-0.
[21] Rao M, Zeng Z, Zhao S. and Tang L. (2018). Effect of levothyroxine supplementation on pregnancy outcomes in women with subclinical hypothyroidism and thyroid autoimmuneity undergoing in vitro fertilization / intracytoplasmic sperm injection: an updated meta-analysis of randomized controlled trials. Reproductive Biology and Endocrinology 16: 92 https://doi.org/10.1186/s12958-018-0410-6.
[22] Casey B. M, Thom E. A, Peaceman A. M, Varner M. W, Sorokin Y, Hirtz D. G, Reddy U. M, Wapner R. J, Thorp Jr. J. M, Saade G, Tita A. TN, Rouse D. J, Sibai B, Iams J. D, Mercer B. M, Tolosa J, Caritis S. N, Van Dorsten J. P. (2017). Treatment of Subclinical Hypothyroidism or Hypothyroxinemia in Pregnancy. N Engl J Med 376: 815-825. DOI: 10.1056/NEJMoa1606205.
[23] Korevaar T. I. M, Derakhshan A, Taylor P. N, Meima M, Chen L, Bliddal S. et al. (2019). Association of Thyroid Function Test Abnormalities and Thyroid Autoimmunity With Preterm Birth. JAMA. 322 (7): 632–641.
[24] Derakhshan A, Peeters RP, Taylor PN, Bliddal S, Carty DM, Meems M, Vaidya B, et al. (2020). Association of maternal thyroid function with birthweight: a systematic review and individual-participant data meta-analysis. Lancet Diabetes Endocrinol. 8 (6): 501-510. doi: 10.1016/S2213-8587(20)30061-9.
[25] Korevaar T. I. M, Steegers E. A. P, Chaker L, Medici M, Jaddoe V. W. V, Visser T. J, de Rijke Y. B. and Peeters R. P. (2017). Thyroid Function and Premature Delivery in TPO Antibody Negative Women: The Added Value of hCG. J Clin Endocrinol Metab 102: 3360–3367.
[26] Korevaar T. I. M, Steegers EA, de Rijke YB, Schalekamp-Timmermans S, Visser WE, Hofman A, Jaddoe VW, Tiemeier H, Visser TJ, Medici M, Peeters RP. (2015). Reference ranges and determinants of total hCG levels during pregnancy: the Generation R Study. Eur J Epidemiol. 30 (9): 1057–1066.
[27] Korevaar T. I. M, de Rijke Y. B, Chaker L, Medici M, Jaddoe V. W. V, Steegers E. A. P, Visser T, Peeters R. P. (2017). Stimulation of Thyroid Function by Human Chorionic Gonadotropin During Pregnancy: A Risk Factor for Thyroid Disease and a Mechanism for Known Risk Factors. Thyroid; 27 (3): 440-450.
[28] Surks M. I. and Hollowell J. G. (2007). Age-specific distribution of serum thyrotropin and antithyroid antibodies in the U.S. population: implications for the prevalence of subclinical hypothyroidism. Journal of Clinical Endocrinology and Metabolism; 92, 12, 4575–4582.
[29] NSI. The population of Bulgarian Republic. National Statistical Institute. 2005. Available at: http://www.nsi.bg/Population/Population.htm.
[30] NSI. 17tH National population census in Bulgaria. National Statistical Institute. 2011. Available at: http://censusresults.nsi.bg/Census/Reports/2/2/R1.aspx.
[31] Borissova A-M, Shinkov A, Vlahov J, Dakovska L, Todorov T. (2012). Screening for endocrine diseases in the Bulgarian population ≥20 years of age (preliminary data). 15tH National Symposium on Endocrinology, April 19-21, 2012, Plovdiv, Bulgaria.
[32] Nathan N, Sullivan SD. (2014). Thyroid disorders during pregnancy. Endocrinol Metab Clin North Am. 43: 573–597.
[33] Borissovа Anna-Maria I., Ivanova Ludmila B, Trifonova Boyana C, Dakovska Lilia N, Mihailova Eugenia N, Vukov Mircho I. (2020). Urine iodine concentration, TPOAb, thyroid hormones in pregnant Bulgarian women – results of a screening study. Endocrinologia, 25 (3): 175-189.
[34] Borissovа A-M, Trifonova B, Ivanova L, Dakovska L, Mihailova E, Vukov M. (2020). Frequency and characteristics of thyroid dysfunction in pregnant women – screening of 547 women in Bulgaria. Medical & Clinical Research, Volume 5 | Issue 9 | 244-250.
[35] Sheehan PM, Nankervis A, Araujo E. Júnior, Da Silva Costa F. (2015). Maternal Thyroid Disease and Preterm Birth: Systematic Review and Meta-Analysis. J Clin Endocrinol Metab 100: 4325–4331.
[36] Feldthusen A-D, Pedersen PL, Larsen J, Kristensen TT, Ellervik C, Kvetny J. (2015). Impaired Fertility Associated with Subclinical Hypothyroidism and Thyroid Autoimmunity: The Danish General Suburban Population Study. Journal of Pregnancy, Article ID 132718, 6 pages http://dx.doi.org/10.1155/2015/132718.
[37] Männistö T, Surcel HM, Ruokonen A, Vääräsmäki M, Pouta A, Bloigu A, Järvelin MR, Hartikainen AL, Suvanto E. (2011). Early pregnancy reference intervals of thyroid hormone concentrations in a thyroid antibody-negative pregnant population. Thyroid 21: 291–298.
[38] Pop VJ, Biondi B, Wijnen HA, Kuppens SM, Lvader H. (2013). Maternal thyroid parameters, body mass index and subsequent weight gain during pregnancy in healthy euthyroid women. Clin Endocrinol (Oxf) 79: 577–583.
Cite This Article
  • APA Style

    Anna-Maria Borissova, Boyana Trifonova, Lilia Dakovska, Eugenia Michaylova, Mircho Vukov. (2020). Factors Determining Thyroid Status in Pregnant Women in Bulgaria. International Journal of Diabetes and Endocrinology, 5(4), 89-95. https://doi.org/10.11648/j.ijde.20200504.17

    Copy | Download

    ACS Style

    Anna-Maria Borissova; Boyana Trifonova; Lilia Dakovska; Eugenia Michaylova; Mircho Vukov. Factors Determining Thyroid Status in Pregnant Women in Bulgaria. Int. J. Diabetes Endocrinol. 2020, 5(4), 89-95. doi: 10.11648/j.ijde.20200504.17

    Copy | Download

    AMA Style

    Anna-Maria Borissova, Boyana Trifonova, Lilia Dakovska, Eugenia Michaylova, Mircho Vukov. Factors Determining Thyroid Status in Pregnant Women in Bulgaria. Int J Diabetes Endocrinol. 2020;5(4):89-95. doi: 10.11648/j.ijde.20200504.17

    Copy | Download

  • @article{10.11648/j.ijde.20200504.17,
      author = {Anna-Maria Borissova and Boyana Trifonova and Lilia Dakovska and Eugenia Michaylova and Mircho Vukov},
      title = {Factors Determining Thyroid Status in Pregnant Women in Bulgaria},
      journal = {International Journal of Diabetes and Endocrinology},
      volume = {5},
      number = {4},
      pages = {89-95},
      doi = {10.11648/j.ijde.20200504.17},
      url = {https://doi.org/10.11648/j.ijde.20200504.17},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijde.20200504.17},
      abstract = {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, PConclusion: 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.},
     year = {2020}
    }
    

    Copy | Download

  • TY  - JOUR
    T1  - Factors Determining Thyroid Status in Pregnant Women in Bulgaria
    AU  - Anna-Maria Borissova
    AU  - Boyana Trifonova
    AU  - Lilia Dakovska
    AU  - Eugenia Michaylova
    AU  - Mircho Vukov
    Y1  - 2020/12/31
    PY  - 2020
    N1  - https://doi.org/10.11648/j.ijde.20200504.17
    DO  - 10.11648/j.ijde.20200504.17
    T2  - International Journal of Diabetes and Endocrinology
    JF  - International Journal of Diabetes and Endocrinology
    JO  - International Journal of Diabetes and Endocrinology
    SP  - 89
    EP  - 95
    PB  - Science Publishing Group
    SN  - 2640-1371
    UR  - https://doi.org/10.11648/j.ijde.20200504.17
    AB  - 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, PConclusion: 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.
    VL  - 5
    IS  - 4
    ER  - 

    Copy | Download

Author Information
  • Clinic of Endocrinology, University Hospital Sofiamed, Sofia, Bulgaria; Faculty of Medicine, Sofia University St. Kliment Ohridski, Sofia, Bulgaria

  • Clinic of Endocrinology, University Hospital Sofiamed, Sofia, Bulgaria; Faculty of Medicine, Sofia University St. Kliment Ohridski, Sofia, Bulgaria

  • Clinic of Endocrinology, University Hospital Sofiamed, Sofia, Bulgaria

  • Clinic of Endocrinology, University Hospital Sofiamed, Sofia, Bulgaria

  • Clinic of Endocrinology, University Hospital Sofiamed, Sofia, Bulgaria

  • Sections