644 Early or threatened labor 
644.0 Threatened premature labor 
644.00 Threatened premature labor unspecified as to episode of care convert 644.00 to ICD-10-CM
644.03 Threatened premature labor antepartum convert 644.03 to ICD-10-CM 644.1 Other threatened labor 644.10 Other threatened labor unspecified as to episode of care convert 644.10 to ICD-10-CM 644.13 Other threatened labor antepartum convert 644.13 to ICD-10-CM 644.2 Early onset of delivery 
644.20 Early onset of delivery unspecified as to episode of care convert 644.20 to ICD-10-CM 644.21 Early onset of delivery delivered with or without antepartum condition convert 644.21 to ICD-10-CM