Background: The fall of serum sodium concentration may happen in hyperemesis gravidarum and subsequently can result into hypotonic hyponatremia. This would cause water to move into the brain and develop cerebral edema manifested with neurologic symptoms. However, adaptive mechanism by brain would lower the cerebral volume to a normal range. On the other hand, rapid correction of chronic hyponatremia would damage the brain cells. The symptoms depicted because of rapid over correction of sodium is known as osmotic demyelination syndrome. Case Presentation: The pregnant lady with hyperemesis gravidarum went to severe hyponatremia. And further, she underwent dilatation and evacuation because of the intrauterine fetal death. The normal saline administered to correct the state of hyponatremia caused the patient to be in depression with catatonia and aphasia. The symptoms were correlated with osmotic demyelinolysis and the event was confirmed with magnetic resonance imaging of brain. Conclusion: The administration of sodium should be performed with utmost cautions and under the supervision of welltrained healthcare providers. Any sign or symptom of neurological abnormalities observed because of overcorrection should be considered seriously.

Keywords: Dyselectrolytemia, hyperemesis, hyponatremia, intrauterine fetal death, osmotic demyelinolysis