Convert to ICD-10-CM: 
626.1 converts approximately to:
- 2015/16 ICD-10-CM N91.5 Oligomenorrhea, unspecified
 ICD-9-CM Volume 2 Index entries containing back-references to 
626.1:
- Hypomenorrhea 626.1
- Menstruation infrequent 626.1 infrequent 626.1
  scanty 626.1 scanty 626.1
 
- Oligomenorrhea 626.1