[No thyroxin dose seemed sufficient--why?]

The health status of a woman with type 1 diabetes was followed during pregnancy in a maternity hospital. In addition to insulin, thyroxine therapy was applied due to hypothyreosis as a consequence of Basedow disease. Nephropathy and significant proteinuria had developed as complications of diabetes, with the proteinuria increasing considerably during pregnancy. Simultaneously thyroxine doses increased to exceptionally high levels. The cause of increasing doses was found to be secretion of thyroxine into urine. The phenomenon has been described earlier, but it is not generally recognized.