Endocrine Abstracts

Management of Thyrotoxicosis in a Non-compliant Pregnant Woman

A 23-year-old woman with Grave's disease presented to thyroid clinic 29 weeks into her first pregnancy having recently moved into the area. She had failed to attend hospital thyroid clinics elsewhere and frequently changed her address.

Despite propylthiouracil 300 mg daily she had marked tremor, tachycardia 100 bpm, ophthalmopathy, and a large smooth goitre. TSH <0.01 mU\/L, fT4 36.5 pmol\/L (12.0- 26.6) fT3 16.7 pmol/L (2.3-6.7). Propylthiouracil was increased to 600mg daily. She defaulted from follow up. At 35 weeks she was admitted for thyrotoxicosis control. TSH <0.01mU\/L, fT4 65.2 pmol\/L, fT3 15.3 pmol/L. She had omitted propylthiouracil due to its bitter taste. Fetal heart rate was 140-160 bpm, biparietal diameter 25th percentile and abdominal circumference 50th percentile. There were fears about her fitness for normal labour or anaesthesia if obstetric intervention was required and the goitre posed potential intubation difficulties. Carbimazole 30 mg daily was substituted. At 38 weeks fT4 42.9 pmol/L, fT3 9.1 pmol/L. Lugol's iodine was given for 7 days. At 39 weeks fT4 27.5 pmol/L, fT3 6.1 pmol/L. Carbimazole was reduced to 20 mg daily. At 40 weeks fT4 22.2 pmol/L. fT3 6.5 pmol/L. Carbimazole was reduced to 15 mg daily. Fetal tachycardia normalised. There was no fetal goitre.

Following spontaneous labour, a healthy euthyroid female infant was delivered 3 days post term. Birth weight was 3.34 kg (50th percentile). Subsequent weight gain was normal. The mother later underwent subtotal thyroidectomy due to continued non-compliance.

This case demonstrates problems with managing thyrotoxicosis in the non-compliant pregnant patient when successful control becomes a race against time.