Overview of thyroid gland characteristics in pregnancy using ultrasonography as an assessment tool
DOI:
https://doi.org/10.18203/2320-1770.ijrcog20223518Keywords:
Thyroid gland, Pregnancy, UltrasonographyAbstract
Thyroid gland is one of the most common gland affected during pregnancy as it responds to the increased physiological demands of iodine and energy during pregnancy. Any thyroid dysfunction can result in abortion, preterm labor or affects fetal neurodevelopment. Various anthropometric factors or genetic factors apart from iodine intake are known to affect the size of thyroid gland. Changes in thyroid gland morphology can be easily measured using ultrasonography as clinically the enlargement can be labelled as goiter. In this review, we aimed to evaluate the changes in thyroid gland during pregnancy and assess the different factors affecting its size across the various studies as the literature data concerning the thyroid gland enlargement during pregnancy is controversial. Various articles on thyroid volume changes during pregnancy from literature were reviewed along with a cross-sectional observation done in a government hospital setup in India, on 240 patients who were divided into 4 groups of 60 patients each which included non-pregnant females in group 1 and pregnant females in all three trimesters respectively in the rest 3 groups. Thyroid gland morphology and its characteristics such as volume, nodularity, echogenicity and vascularity were measured using high frequency ultrasonography in each group and then compared. Thyroid volume in the third trimester group (7.24±1.16 ml) was found to be significantly greater (p<0.001) than in the non-pregnant group (5.44±0.82 ml). BMI was found to be the highest in third trimester group as expected. Even in iodine sufficient areas we found thyroid gland volume to increase during pregnancy from non-pregnant group along with thyroid gland nodularity. Vascularity assessed based on CDFS pattern shows pattern I to be most common. Variation in thyroid gland characteristics between pregnant and non-pregnant controls was found.
References
Glinoer D, DeNayer P, Bourdoux P, Lemone M, Robyn C, Steirteghem AV, et al. Regulation of maternal thyroid during pregnancy. J Clin Endocrinol Metab. 1990;71(2):276-87.
Karger S, Schötz S, Stumvoll M, Berger F, Führer D. Impact of pregnancy on prevalence of goitre and nodular thyroid disease in women living in a region of borderline sufficient iodine supply. Horm Metab Res. 2010;42(2):137-42.
Brander A, Kivisaari L. Ultrasonography of the thyroid during pregnancy. J Clin Ultrasound. 1989;17(6):403-6.
Brunn J, Block U, Ruf G, Bos I, Kunze WP, Scriba PC. Volumetry of thyroid lobes using real‐time sonography. Dtsch Med Wochenschr. 1981;106(41):1338-40.
Bogazzi F, Bartalena L, Brogioni S, Burelli A, Manetti L, Tanda ML, et al. Thyroid vascularity and blood flow are not dependent on serum thyroid hormone levels: studies in vivo by color flow Doppler sonography. Eur J Endocrinol. 1999;140(5):452-6.
Elebrashy I, Eldein HK, Abd-Elstar H, Ghanem N, Mousa S, Assem M, et al. Assessment of thyroid functions and thyroid volume in normal pregnant Egyptian females. Gynecol Endocrinol. 2020;36(2):122-5.
Sahin SB, Ogullar S, Ural UM, Ilkkilic K, Metin Y, Ayaz T. Alterations of thyroid volume and nodular size during and after pregnancy in a severe iodine‐deficient area. Clin Endocrinol. 2014;81(5):762-8.
Vannucchi G, Covelli D, Vigo B, Perrino M, Mondina L, Fugazzola L. Thyroid volume and serum calcitonin changes during pregnancy. J Endocrinol Investigat. 2017;40(7):727-32.
Sultanalieva RB, Mamutova S, Haar F. The current salt iodization strategy in Kyrgyzstan ensures sufficient iodine nutrition among school-age children but not pregnant women. Pub Health Nutri. 2010;13(5):623-30.
Krasnodebska-Kiljańska M, Kondracka A, Bartoszewicz Z, Niedźwiedzka B, Ołtarzewski M, Grzesiuk W, Bednarczuk T, et al. Iodine supply and thyroid function in the group of healthy pregnant women living in Warsaw. Polski merkuriusz lekarski: organ. Pol Merkur Lekarski. 2013;34(202):200-4.
Berghout A, Endert E, Ross A, Hogerzeil HV, Smits NJ, Wiersinga WM. Thyroid function and thyroid size in normal pregnant women living in an iodine replete area. Clin Endocrinol (Oxf). 1994;41(3):375-9.
Azizi F, Aminorroya A, Hedayati M, Rezvanian H, Amini M, Mirmiran P. Urinary iodine excretion in pregnant women residing in areas with adequate iodine intake. Public Health Nutri. 2003;6(1):95-8.
Jaiswal N, Melse-Boonstra A, Sharma SK, Srinivasan K, Zimmermann MB. The iodized salt programme in Bangalore, India provides adequate iodine intakes in pregnant women and more-than-adequate iodine intakes in their children. Public Health Nutri. 2015;18(3):403-13.
Kianpour M, Aminorroaya A, Amini M, Feizi A, Janghorbani M, Shokri S, et al. Reference intervals for thyroid hormones during the first trimester of gestation: a report from an area with a sufficient iodine level. Horm Metab Res. 2019;51(3):165-171.
Dashe JS, Casey BM, Wells CE, McIntire DD, Byrd EW, Leveno KJ, et al. Thyroid-stimulating hormone in singleton and twin pregnancy: Importance of gestational age-specific reference ranges. Obstet Gynecol. 2005;106(4):753-7.
Guo W, Wang W, Jin Y, Chen W, Chen L, Lin L, et al. Trimester-specific thyroid function in pregnant women with different iodine statuses. Ann Nutr Metab. 2020;76(3):165-174.
Tuccilli C, Baldini E, Truppa E, D'Auria B, De Quattro D, Cacciola G, et al. Iodine deficiency in pregnancy: Still a health issue for the women of Cassino city, Italy. Nutrition. 2018;50:60-5.
Gao M, Chen Y, Zhang Y, Sun H, Zhang Q, Chen W, et al. Thyroglobulin can be a functional biomarker of iodine deficiency, thyroid nodules, and goiter in Chinese pregnant women. Asia Pac J Clin Nutr. 2020;29(1):27-34.
Hegedüs L. The thyroid nodule. N Engl J Med. 2004;351(17):1764-71.
Vander JB, Gaston EA, Dawber TR. The significance of nontoxic thyroid nodules: final report of a 15-year study of the incidence of thyroid malignancy. Ann Intern Med. 1968;69(3):537-40.
Ezzat S, Sarti DA, Cain DR, Braunstein GD. Thyroid incidentalomas: prevalence by palpation and ultrasonography. Arch Intern Med. 1994;154(16):1838-40.
Tan GH, Gharib H. Thyroid incidentalomas: management approaches to nonpalpable nodules discovered incidentally on thyroid imaging. Ann Intern Med. 1997;126(3):226-31.
Struve CW, Haupt S, Ohlen S. Influence of frequency of previous pregnancies on the prevalence of thyroid nodules in women without clinical evidence of thyroid disease. Thyroid. 1993;3(1):7-9.
Glinoer D, Soto MF, Bourdoux P, Lejeune B, Delange F, Lemone M, et al. Pregnancy in patients with mild thyroid abnormalities: maternal and neonatal repercussions. J Clin Endocrinol Metabol. 1991;73(2):421-7.
Kung AW, Chau MT, Lao TT, Tam SC, Low LC. The effect of pregnancy on thyroid nodule formation. J Clin Endocrinol Metabol. 2002;87(3):1010-4.
Fister P, Gaberšček S, Zaletel K, Krhin B, Geršak K, Hojker S. Thyroid volume changes during pregnancy and after delivery in an iodine-sufficient Republic of Slovenia. Eur J Obstet Gynecol Reproduct Biol. 2009;145(1):45-8.
