Central pontine myelinolysis (CPM) has been reported in women with severe hyperemesis gravidarum-induced hyponatremia followed by rapid correction. Gestational diabetes with adipsia complicated by acute hypernatremia resulting in CPM has never been reported. Here is a case of a disabled female who presented with polydipsia, polyuria, seizures, fetal death in utero, hyperglycemia, and hyper-osmolar hypernatremia on her 31st gestational week. The dead fetus was delivered and the patient's plasma glucose and sodium were later stabilized. When the patient developed quadriplegia and respiratory failure 5 days later, brain magnetic resonance imaging showed central pontine and extra-pontine myelinolysis. Gestational diabetes complicated by hyper-osmolar crisis may cause fetal death and severe neurologic sequela. Early recognition and delivery of the fetus and placenta may improve the electrolyte and fluid imbalance.