Poster Presentation Annual Meetings of the Endocrine Society of Australia and Society for Reproductive Biology and Australia and New Zealand Bone and Mineral Society 2016

The antenatal care of a woman with thyroid hormone resistance (#416)

Chau Thien Tay 1 , Anthony Zimmermann 1 , Anjana Radhakutty 1
  1. Lyell McEwin Hospital, Elizabeth Vale, SA, Australia

RTH is a rare syndrome of reduced end organ sensitivity to circulating thyroid hormones [1]. It is usually inherited in an autosomal dominant fashion with up to 85% of cases due to mutation in the thyroid hormone receptor β (THRβ) located in chromosome 3 [2,3]. RTH has a variable clinical phenotype where the patients can be euthyroid, hypothyroid, thyrotoxic or coexisting hypothyroid and thyrotoxic [4]. Asymptomatic patients do not require treatment; otherwise, treatment options aiming to alleviate symptoms can be offered [2].

The implications of Thyroid hormone resistance (RTH) on pregnancy are not well understood, nor is there any evidence based guidelines available for the antenatal care of the kindred. Literature has suggested a 3- to 4- fold increase risk of miscarriage in female patients with RTH compared to the normal population. The risk is presumed higher if they carry an unaffected foetus [5]. Unaffected infants born to affected mothers also had suppressed TSH at birth and a significantly lower birth weight than their affected siblings [5]. These data indicate a direct toxic effect of thyroid hormone excess on the unaffected foetus.

We report a case of a young woman with known RTH who is currently pregnant. Our discussion will review the available published reports on pregnancy in females with RTH and our approach to the management of her antenatal care and foetal monitoring.


  1. Agrawal N, Goyal R, Rastogi A, Naik D, Singh S. Thyroid hormone resistance. Postgraduate Medical Journal. 2008;84(995):473-477.
  2. Weiss R, Dumitrescu A, Refetoff S. Approach to the Patient with Resistance to Thyroid Hormone and Pregnancy. The Journal of Clinical Endocrinology & Metabolism. 2010;95(7):3094-3102.
  3. Beck-Peccoz P, Mannavola D, Persani L. Syndromes of thyroid hormone resistance. Annales d'Endocrinologie. 2005;66(3):264-269.
  4. Weiss Refetoff S. Resistance to Thyroid Hormone. Reviews in Endocrine & Metabolic Disorders. 1st ed. Boston: Kluwer Academic Publishers; 2000. p. 97-108.
  5. Anselmo J, Cao D, Karrison T, Weiss R, Reetoff S. Foetal Loss Associated With Excess Thyroid Hormone Exposure. Obstetrical & Gynecological Survey. 2005;60(2):82-83.