Retrosternal goitre: a cause of dyspnoea in pregnancy.

During pregnancy, the thyroid undergoes several changes including altered function and gland enlargement. We describe the management of a 38-week pregnant woman presenting with cough and increasing breathlessness. She gave a 5-year history of asthma which initially obscured the final diagnosis of upper-airway obstruction secondary to tracheal compression by a large retrosternal goitre. Once this was recognized, management was straightforward. Delivery by caesarean section was carried out under epidural anaesthesia, following which her symptoms rapidly resolved. A subtotal thyroidectomy was performed 4 weeks later under general anaesthesia, again without incident. We outline the normal physiological changes that occur to the thyroid gland during pregnancy and also highlight the value of the flow volume loop in the evaluation of airway obstruction.