BACKGROUND:King syndrome is characterized by the presence of a nonspecific myopathy, a susceptibility to malignant hyperthermia, and dysmorphic features similar to the phenotype seen in Noonan syndrome. CASE:A young primigravida with King syndrome presented at 19 weeks' gestation. The patient required nocturnal mechanical ventilation via tracheostomy, and there was concern that the patient would become increasingly dependent on mechanical ventilation during pregnancy. The patient underwent a forceps-assisted delivery at 35 weeks' gestation, and both the patient and her infant did well and were discharged on postpartum day 3. CONCLUSION:In the gravida with King syndrome, agents that may trigger malignant hyperthermia should be avoided. Significant myopathy may result in respiratory compromise, and a multidisciplinary approach is necessary to optimize maternal and fetal outcome.