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

Neonatal complications of Graves’ disease in pregnancy (#393)

Josephine McCarthy 1 , Shoshana Sztal-Mazer 1
  1. Department of Endocrinology and Diabetes, Alfred Health, Prahran, VIC, Australia

Introduction: Neonatal hyperthyroidism is a rare condition with significant sequela and up to 25% mortality if left untreated. Maternal hyperthyroidism occurs in 0.2-1.0% of pregnancies, most commonly due to Graves’ disease. Neonatal thyrotoxicosis, due to transplacental transfer of thyroid stimulating hormone (TSH) receptor antibodies (TRAbs), is seen in 1-5% of neonates born to mothers with Graves’ disease.

 

Case summary: Ms K.F. is a 33 year old lady referred to endocrine in pregnancy clinic for management of hypothyroidism. Ms K.F’s first trimester TSH was elevated at 3.15 pmol/L. On detailed questioning Ms K.F. revealed a significant history of Graves’ disease with ophthalmopathy for which she had a thyroidectomy and ocular surgery. On further testing the TRAb titre was found to be markedly elevated at 37.7 IU/L. Ms K.F. and her foetus were closely monitored throughout the pregnancy noting borderline foetal tachycardia. Severe neonatal thyrotoxicosis ensued, requiring a 2 week admission. This diagnosis was delayed due to inadequate neonatal testing. I will elaborate on the case including a review of the literature and discuss potential pitfalls in diagnosis of maternal Graves’ disease and neonatal thyrotoxicosis.          

 

Learning Points:

  • TRAbs cross the placenta and can cause foetal and/or neonatal thyrotoxicosis
  • TRAbs should be checked early in pregnancy in those with Graves’ Disease, even those previously treated with radioiodine or surgery as TRAbs may remain elevated
  • Maternal TRAbs >3-5 times the upper limit of normal increases the risk of foetal and/or neonatal hyperthyroidism
  • Neonates born to mothers with Graves’ require complete thyroid function testing which includes free T4, free T3 and TSH
  • Thyroid hormone levels are not tested on the Guthrie newborn heel prick test, which screens for neonatal hypothyroidism and hence only assesses TSH
  • A multidisciplinary approach involving careful communication between the endocrine, obstetric and paediatric team is essential
  1. Maguire A., Srinivasan S., Benitez-Aguirre P., Silink M., Craig M., Munns C., Cowell C., Howard N., Ambler G., Donaghue K. Paediatric Diabetes. Conference: Joint Annual Conference of the International Society for Paediatric and Adolescent Diabetes and Australasian Paediatric Endocrine Group, ISPAD+APEG 2015 Brisbane, QLD Australia. Conference Publication. 2015; 16:144.
  2. Okosieme OE, Lazarus J. Hyperthyroidism in Pregnancy. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000- [cited 2016 Jun 2]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK279107
  3. Barbesino G., Tomer Y. Clinical review: Clinical utility of TSH receptor antibodies. J Clin Endocrinol Metab. 2013; 98 (6):2247-2255
  4. Demers LM, Spencer CA. Laboratory medicine practice guidelines: laboratory support for the diagnosis and monitoring of thyroid disease. Clin Endocrinol (Oxf) 2003; 58: 138–140.
  5. Luton D., Le Gac I., Vuillard E., Castanet M., Guibourdenche J., Noel M., Toubert M.-E., Leger J., Boissinot C., Schlageter M.-H., Garel C., Tebeka B., Oury J.-F., Czernichow P., Polak M. Management of Graves' disease during pregnancy: The key role of foetal thyroid gland monitoring. J Clin Endocrinol Metab. 2005; 90 (11):6093-6098.
  6. Higuchi R., Kumagai T., Kobayashi M., Minami T., Koyama H., Ishii Y. Short-term hyperthyroidism followed by transient pituitary hypothyroidism in a very low birth weight infant born to a mother with uncontrolled Graves' disease. Paediatrics. 2007: 107 (4): E57.
  7. Luton D, Le Gac I, Vuillard E, Castanet M, Guibourdenche J, Noel M, Toubert ME, Léger J, Boissinot C, Schlageter, MH, Garel C, Tébeka B, Oury JF, Czernichow P, Polak M. Management of Graves’ disease during pregnancy: the key role of foetal thyroid gland monitoring. J Clin Endocrinol Metab. 2005; 90:6093–6098.
  8. Abalovich M., Amino N., Barbour L.A., Cobin R.H., De Groot L.J., Glinoer D., Mandel S.J., Stagnaro-Green A., Edwards H. Clinical practice guideline: Management of thyroid dysfunction during pregnancy and postpartum: An endocrine society clinical practice guideline. J Clin Endocrinol Metab. 2007; 92 (8): S1-S47.
  9. Papendieck P, Chiesa A, Prieto L, Gruñeiro-Papendieck L. Thyroid disorders of neonates born to mothers with Graves’ disease. J Pediatr Endocrinol Metab. 2009; 22:547–553.