Severe hyponatraemia peripartum associated with omeprazole therapy.

Hyponatraemia is the most commonly encountered electrolyte abnormality in pregnancy and may be associated with adverse maternal and neonatal outcomes. Rapid onset, severe hyponatraemia has been reported with proton-pump inhibitor therapy in non-pregnant individuals. Gastro-oesophageal reflux is very common during pregnancy, and proton-pump inhibitors are available without a prescription in many countries. A case of severe maternal hyponatraemia in the setting of recent omeprazole therapy is presented. Health professionals should be aware of this complication given the availability of proton-pump inhibitors without prescription and high rates of gestational gastro-oesophageal reflux.