Treatment of thyrotoxicosis in pregnancy: Three cases exemplifying multi-specialty involvement


E Ferran, K Mahbubani,† H Yap, R Dua,† A Yazdi, N Tolley, C Yu, J Therry, E Greco, J Cox, V Bravis, S Robinson. St Maryís Hospital, Imperial College.


Introduction: Maternal thyrotoxicosis in pregnancy can be managed with thionamide drugs or surgery. The ideal pregnancy related management strategy is unclear and will depend on the particular case.


Case 1: 33 year old lady (G7P3) presented at 6 weeks gestation with severe thyrotoxicosis secondary to post-partum Gravesí disease. Propylthiouracil (PTU) was not tolerated and she was given supraoptimal dosage of Carbimazole. Her thyrotoxicosis remained severely undertreated. She eventually had a planned thyroidectomy at 19 weeks gestation. She has not yet delivered.


Case 2: 38 year old (G1P0) presented with hyperemesis thyrotoxicosis and atrial fibrillation at 12 weeks gestation, whilst thyroid function tests were only controlled with high dose PTU. Thyroidectomy was planned and carried out at 18 weeks gestation. The neonate birth weight was 3.66kg.


Case 3: 32 year old (G3P0) was diagnosed with Gravesí thyrotoxicosis but failed to enter remission despite maximal antithyroid drug therapy. She was scheduled for thyroidectomy but fell pregnant prior to her surgery. She was treated with high dose PTU, in safe preparation towards surgery, and had a thyroidectomy at 20 weeks gestation. She has not yet delivered.

For all three cases pre-operative preparation included an attempt to control thyroid hormone levels with Lugolís iodine, beta-blockade for cardiac protection and giving vitamin D supplementation.




Case 1

Case 2

Case 3

TSH (mU/L)

< 0.01

< 0.01

< 0.01

T3 (pmol/L)




T4 (pmol/L)




TSH Receptor Ab (u/ml)





Discussion points: The cases exemplify the importance of coordination of care in the management of these complex and life threatening cases between the endocrine, obstetrics, midwifery, ENT and anaesthetic teams. They illustrate the importance of using safe doses of thionamide drugs, in an attempt to control thyroid function before the third trimester, as well as the significance of good pre-operative preparation, which has great impact on both maternal and fetal outcomes.