Assessment of Maternal Health and Thyroid Activity by Determination of TSH, fT3 and fT4 in Pregnant Women Taking a Vitamin Supplement Containing Iodine


  • Vincenzo De Leo Department of Molecular and Development Medicine, Obstetrics and Gynecologic Unit, Policlinico Le Scotte, University of Siena, Italy
  • Valentina Cappelli Department of Molecular and Development Medicine, Obstetrics and Gynecologic Unit, Policlinico Le Scotte, University of Siena, Italy
  • Maria Concetta Musacchio Department of Molecular and Development Medicine, Obstetrics and Gynecologic Unit, Policlinico Le Scotte, University of Siena, Italy
  • Giuseppe Morgante Department of Molecular and Development Medicine, Obstetrics and Gynecologic Unit, Policlinico Le Scotte, University of Siena, Italy
  • Claudio Benvenuti Medical Department, Rottapharm Madaus, Monza, Italy



Pregnancy, thyroid, hyperemesis, multivitamins, iodine.


Background: During pregnancy, important changes occur in maternal thyroid function. The thyrotropic activity of human chorionic gonadotropin (hCG) has been studied by many authors. This hormone has similarities to thyroid-stimulating hormone (TSH). This has led to the supposition that hCG is indirectly involved in thyroid stimulation.

In pregnancy, TSH is inhibited, with low levels of fT3 and fT4; in recent years, some authors have found a relationship between raised thyroid hormones and the onset of hyperemesis gravidarum. Thus, increasing or starting levothyroxine therapy is not indicated in the first trimester of pregnancy. Nutritional supplements may have an important role; in fact, iodine may encourage more physiological thyroid function and could affect the onset or absence of hyperemesis gravidarum.

Materials and Methods: To identify the incidence of hyperemesis gravidarum in two groups of women treated with multivitamin supplementation with or without iodine, we analysed TSH, fT3 and fT4 levels and the severity of symptoms in pregnant women with nausea and vomiting.

Results: TSH levels were significantly reduced in the group treated with iodine. fT3 and fT4 showed a significant decrease in the group treated with the multivitamin supplement containing iodine.

Conclusions: Our results also show that the multivitamin supplement containing iodine was more effective in controlling the onset of hyperemesis gravidarum, improving TSH, fT3 and fT4 levels.


Gadsby R, Barnie-Adshead AM, Jagger C. A prospective study of nausea and vomiting during pregnancy. Br J Gen Pract 1993; 43(371): 245-8.

Einarson A, Maltepe C, Boskovic R, Koren G. Treatment of nausea and vomiting in pregnancy: an updated algorithm. Can Fam Physician 2007; 53(12): 2109-11.

Weigel MM, Weigel RM. Nausea and vomiting of early pregnancy and pregnancy outcome. An epidemiological study. Br J Obstet Gynaecol 1989; 96(11): 1304-11.

De Leo V, LA Marca A, Lanzetta D, Morgante G. Thyroid function in early pregnancy I: Thyroid-stimulating hormone response to thyreotropin-releasing hormone. Gynecol Endocrinol 1998; 12: 191-6.

Negro R, Mestman JH. Thyroid disease in pregnancy. Best Pract Res Clin Endocrinol Metab 2011; 25: 927-43.

Nisula BC, Morgan FJ, Canfield RE. Evidence that chorionic gonadotropin has intrinsic thyrotropic activity. Biochem Biophys Res Commun 1974; 10; 59(1): 86-91.

Yoshikawa N, Nishikawa M, Horimoto M, Yoshimura M, Sawaragi S, Horikoshi Y, et al. Thyroid-stimulating activity in sera of normal pregnant women. J Clin Endocrinol Metab 1989; 69(4): 891-5.

Davies TF, Platzer M. hCG-induced TSH receptor activation and growth acceleration in FRTL-5 thyroid cells. Endocrinology 1986; 118(5): 2149-51.

Hershman JM, Lee HY, Sugawara M, Mirell CJ, Pang XP, Yanagisawa M, Pekary AE. Human chorionic gonadotropin stimulates iodine uptake, adenylate cyclase, and deoxyribonucleic acid synthesis in cultured rat thyroid cells. J Clin Endocrinol Metab 1988; 67(1): 74-9.

American College of Obstetrics and Gynecology. ACOG practice bulletin. Thyroid disease in pregnancy. Number 37, August 2002. American College of Obstetrics and Gynecology. Int J Gynecol Obstet 2002; 79(2): 171-80. 78 International Journal of Gynecological and Obstetrical Research, 2013, Vol. 1, No. 2 De Leo et al.

Lazarus JH. Thyroid disorders associated with pregnancy: etiology, diagnosis, and management. Treat Endocrinol 2005; 4(1): 31-4.

Hovdenak N, Haram K. Influence of mineral and vitamin supplements on pregnancy outcome. Eur J Obstet Gynecol Reprod Biol 2012; 164: 127-32.

Rodien P, Jordan N, Lefevre A, Royer J, Vasseur C, Savagner F, Bourdelot A, Rohmer V. Abnormal stimulation of the thyrotrophin receptor during gestation. Hum Reprod Update 2004; 10(2): 95-105.

Jerome M, Hershman. Physiological and pathological aspects of the effect of human chorionic gonadotropin on the thyroid. Best Pract Res Clin Endocrinol Metab 2004; 18: 249- 65.

Bhupinder KG, Promila J, Raj K, Shweta T, Namrata S, Anupama G. A study of thyroid status in hyperemesis gravidarum. Indian J Clin Biochem 2007; 22(1): 148-51.

Neale, DM, Chung Cootauco A, Burrow G. Thyroid disease in pregnancy. Clin Perinatol 2007; 34: 543-57.

Gartner R. Thyroid disorders during pregnancy. Dtsch Med Wochenschr 2009; 134(3): 83-6.

Ebrahimi N, Maltepe C, Einarson A. Optimal management of nausea and vomiting of pregnancy. Int J Womens Health 2010; 2: 241-8.

Parkes IL, Schenker JG, Shufaro Y. Thyroid disorders during pregnancy. Gynecol Endocrinol 2012; 28(12): 993-8.

Goodwin TM, Montoro M, Mestman JH, Pekary AE, Hershman JM. The role of chorionic gonadotropin in transient hyperthyroidism of hyperemesis gravidarum. J Clin Endocrinol Metab 1992; 75(5): 1333-7.

Kus NK, Koyuncu F. Hyperemesis gravidarum: current concepts and management. Postgrad Med J 2002; 78: 76-9.

Lazarus JH. Thyroxine excess and pregnancy. Acta Med Austriaca 1994; 21(2): 53-6.

Perez-Lopez FR. Iodine and thyroid hormones during pregnancy and postpartum. Gynecol Endocrinol 2007; 23(7): 414-28.

Shaw GM, Carmichael SL, Yang W, Siega-Riz AM. Periconceptional intake of folic acid and food folate and risks of preterm delivery. National Birth Defects Prevention Study. Am J Perinatol 2011; 28(10): 747-52.