Letter to the Editor Letter regarding: Managing severe peripartum hyponatraemia: A case report, Obstetric Medicine: The Medicine of Pregnancy To the Editor,

I thank Snow et al. for their case report on the management of severe peripartum hyponatraemia.1 Severe hyponatraemia has been described in the peripartum period with preeclampsia, ingestion or infusion of excess fluids during delivery, prolonged infusion of oxyto-cin and glucocorticoid deficiency due to Sheehan’s syndrome. The authors attributed severe hyponatraemia in the subject presented to syndrome of inappropriate antidiuretic hormone secretion (SIADH). The diagnosis of SIADH requires normal adrenal, thyroid and renal function. As stated by the authors, the panel of hormonal tests in the subject described are strongly suggestive of hypopituitarism with a low free thyroxine, low gonadotropins and an inappropriately low serum prolactin for the peripartum period in a mother attempting to lactate. The serum cortisol was not provided. Glucocorticoid deficiency may result in an inability to excrete dilute urine due to a combination of elevated levels of arginine vasopressin and increased water permeabil