Convert ICD-10 Code G44.81 to ICD-9

Source ICD-10 Code		Target ICD-9 Code
G44.81 Hypnic headache		339.81 Hypnic headache

ICD-10 to ICD-9 crosswalk for code G44.81 - hypnic headache based on the most recent General Equivalence Mappings (GEMS) information.