645 Late pregnancy 
645.1 Post term pregnancy 
645.10 Post term pregnancy, unspecified as to episode of care or not applicable convert 645.10 to ICD-10-CM 645.11 Post term pregnancy, delivered, with or without mention of antepartum condition convert 645.11 to ICD-10-CM
645.13 Post term pregnancy, antepartum condition or complication convert 645.13 to ICD-10-CM 645.2 Prolonged pregnancy 
645.20 Prolonged pregnancy, unspecified as to episode of care or not applicable convert 645.20 to ICD-10-CM 645.21 Prolonged pregnancy, delivered, with or without mention of antepartum condition convert 645.21 to ICD-10-CM 645.23 Prolonged pregnancy, antepartum condition or complication convert 645.23 to ICD-10-CM