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P08.21 ICD-10-CM Code: Post-term newborn

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
2 inclusion terms

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for P08.21 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on P08.21 itself; “inherited from” names the category or block whose note applies here.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • the listed conditions, without further specification, as causes of morbidity or additional care, in newborn

Source: inherited from P08

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Newborn with gestation period over 40 completed weeks to 42 completed weeks

Code Overview

Post-term newborn is a billable ICD-10-CM diagnosis code (P08.21).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (2)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 1 MS-DRG: DRG 795 (MDC 15).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):PNL013 — Other specified and unspecified perinatal conditions (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Other specified and unspecified perinatal conditions).

P08.0 — Exceptionally large newborn baby, P08.1 — Other heavy for gestational age newborn, P08.22 — Prolonged gestation of newborn, P09 — Abnormal findings on neonatal screening, P09.1 — Abnormal findings on neonatal screening for inborn errors of metabolism, P09.2 — Abnormal findings on neonatal screening for congenital endocrine disease, P09.3 — Abnormal findings on neonatal screening for congenital hematologic disorders, P09.4 — Abnormal findings on neonatal screening for cystic fibrosis, P09.5 — Abnormal findings on neonatal screening for critical congenital heart disease, P09.6 — Abnormal findings on neonatal hearing screening, P09.8 — Other abnormal findings on neonatal screening, P09.9 — Abnormal findings on neonatal screening, unspecified, P22.1 — Transient tachypnea of newborn, P29.0 — Neonatal cardiac failure, P29.11 — Neonatal tachycardia, P29.12 — Neonatal bradycardia, P29.2 — Neonatal hypertension, P29.3 — Persistent fetal circulation, P29.30 — Pulmonary hypertension of newborn, P29.38 — Other persistent fetal circulation, +74 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Newborn”; these codes share that main term but sit in a different category of the Tabular List.

P04.41 — Newborn affected by maternal use of cocaine (affected by, cocaine), P04.42 — Newborn affected by maternal use of hallucinogens (affected by, drugs of addiction, hallucinogens), P04.49 — Newborn affected by maternal use of other drugs of addiction (affected by, methamphetamine), P04.5 — Newborn affected by maternal use of nutritional chemical substances (affected by, nutritional supplements), P04.6 — Newborn affected by maternal exposure to environmental chemical substances (affected by, environmental chemicals), P04.81 — Newborn affected by maternal use of cannabis (affected by, maternal, cannabis), P04.89 — Newborn affected by other maternal noxious substances (affected by, noxious substances transmitted via placenta or breast milk, specified NEC), P04.9 — Newborn affected by maternal noxious substance, unspecified (affected by, noxious substances transmitted via placenta or breast milk), P05.2 — Newborn affected by fetal (intrauterine) malnutrition not light or small for gestational age (affected by, fetal, malnutrition not light or small for gestational age), P05.9 — Newborn affected by slow intrauterine growth, unspecified (affected by, slow intrauterine growth), P28.2 — Cyanotic attacks of newborn (affected by, cyanosis), P28.30 — Primary sleep apnea of newborn, unspecified (apnea, sleep), P28.40 — Unspecified apnea of newborn (apnea), P28.42 — Obstructive apnea of newborn (apnea, obstructive), P28.81 — Respiratory arrest of newborn (affected by, respiratory arrest), P29.11 — Neonatal tachycardia (affected by, heart rate abnormalities, tachycardia), P29.12 — Neonatal bradycardia (affected by, heart rate abnormalities, bradycardia), P29.81 — Cardiac arrest of newborn (affected by, cardiac arrest), P36.0 — Sepsis of newborn due to streptococcus, group B (sepsis, due to, Streptococcus, group B), P36.10 — Sepsis of newborn due to unspecified streptococci (sepsis, due to, Streptococcus), +149 more

Contextual Map

Every relationship of P08.21 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

Index entries

  • Newborn (infant) (liveborn) (singleton), post-term[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Post-term (40-42 weeks) (pregnancy) (mother), infant[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "P08.21 — Post-term newborn." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/p08.21-post-term-newborn

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Post-term newborn

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to P08.21 in its code family, with their registry titles.

View all codes in the P08 family