P07.21
Extreme immaturity of newborn, gestational age less than 23 completed weeks
P07.21 (also written P0721) is a billable ICD-10-CM diagnosis code for extreme immaturity of newborn, gestational age less than 23 completed weeks. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 27 codes in category P07 (Disorders of newborn related to short gestation and low birth weight, not elsewhere classified). The Alphabetic Index lists it under 1 entry. Its coding notes include 5 Excludes2 entries.
Guidelines tips
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
Chapter 16 codes are never used on the maternal record, and chapter 15 codes are never used on the newborn record. Chapter 16 codes can be used for life if the condition persists.
Prematurity is coded only when documented. When birth weight and gestational age are both available, two P07 codes are assigned, weight first. P07 can also apply to an older child or adult whose health is still affected.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (5 notes)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- tetanus neonatorum (A33)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Other clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Includes
Further defines or gives examples of the content of the category.
- the listed conditions, without further specification, as the cause of morbidity or additional care, in newborn
Also from chapter/block level (1 note)
- conditions that have their origin in the fetal or perinatal period (before birth through the first 28 days after birth) even if morbidity occurs later
Inclusion terms
Conditions classified to this code.
- Extreme immaturity of newborn, gestational age less than 23 weeks, 0 days
Notes
- When both birth weight and gestational age of the newborn are available, both should be coded with birth weight sequenced before gestational age
Also from chapter/block level (1 note)
- Codes from this chapter are for use on newborn records only, never on maternal records
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 1 entry