Diabetes insipidus complicating apoplexy during pregnancy: the potential use of copeptin

Pituitary apoplexy during pregnancy is rare but important to recognise, particularly in the hyperoestrogenaemic state when known lactotroph hyperplasia occurs. Untreated, the complication rates from pituitary adenomas depend upon the size of the adenoma before pregnancy. A history of thirst plus polydipsia during pregnancy raises suspicion for diabetes insipidus and a 24-h urine collection quantifying polyuria with an inappropriately low urine osmolality confirms the diagnosis. Further evaluation for assessing diabetes insipidus in pregnancy may be facilitated by the use of a copeptin.