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O99.21 ICD-10-CM Code: Obesity complicating pregnancy, childbirth, and the puerperium

Compare with another code for O99.21Check this code on a claim

Billing Status: NO. This is a non-billable ICD-10-CM code: report a more specific billable code beneath it.

Coding at a Glance

Tabular directives
1 inclusion term · 4 Excludes2 · 2 use-additional codes

Not billable · FY2027A non-billable heading in the tabular list: report a more specific code beneath it.

What you need to know

Source: CMS/NCHS Official ICD-10-CM tabular notes, quoted. From the CMS/NCHS tabular list for the release in force. A note the category or block publishes applies to this code too, and is marked with where it comes from.

Use additional codeReport with this code when documented
  • Use additional code to identify the type of obesity (E66.-)
  • Use additional code to identify specific condition (from O99)
Excludes2Not included here; may be reported together
  • diabetes mellitus (O24.-) (from O99.2)
  • malnutrition (O25.-) (from O99.2)
  • postpartum thyroiditis (O90.5) (from O99.2)
  • when the reason for maternal care is that the condition is known or suspected to have affected the fetus (O35-O36) (from O99)
Includesfrom O99What O99 covers
  • conditions which complicate the pregnant state, are aggravated by the pregnancy or are a main reason for obstetric care

Where it sits Source: CMS/NCHS

Under:Chapter 15: Pregnancy, Childbirth and the PuerperiumO94-O9A Other obstetric conditions, not elsewhere classifiedO99 Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperiumO99.2 Endocrine, nutritional and metabolic diseases complicating pregnancy, childbirth and the puerperium

Codes under O99.21 (6)

  • O99.210Obesity complicating pregnancy, unspecified trimesterBillable
  • O99.211Obesity complicating pregnancy, first trimesterBillable
  • O99.212Obesity complicating pregnancy, second trimesterBillable
  • O99.213Obesity complicating pregnancy, third trimesterBillable
  • O99.214Obesity complicating childbirthBillable
  • O99.215Obesity complicating the puerperiumBillable

Most relevant related codes MedCoder-derived

Read off the official notes above and this code’s own position in the tabular list. Which to report is a documentation question; Compare shows the two side by side.

CompareCheck ClaimView Related Codes

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for O99.21 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on O99.21 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.

  • conditions which complicate the pregnant state, are aggravated by the pregnancy or are a main reason for obstetric care

Source: inherited from O99

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code to identify the type of obesity (E66.-)
  • Use additional code to identify specific condition inherited from O99

Coder workflow for O99.21

MedCoder structured workflow — derived from this code’s own official record

Before you code O99.21

  1. O99.21 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

    ReviewO99.210, O99.211, O99.212, O99.213, O99.214, O99.215

    See the relationships section · Guide: How to choose an ICD-10-CM code →

  2. Confirm the condition is documented as complicating the pregnancy, childbirth, or the puerperium, and check the trimester where the code carries one and the fetus character where the category requires it. Chapter 15 codes belong on the maternal record only and take sequencing priority over codes from other chapters. It is the provider’s responsibility to state that a condition is not affecting the pregnancy; the trimester is assigned from the documentation (Guidelines I.C.15.a, I.C.15.a.1, I.C.15.a.3).

    Guide: How to choose an ICD-10-CM code →

Choose the right path

  1. Does the documentation support one of the more specific codes beneath O99.21?
    Yes → Select that code and continue the checks below on its own page.
    No → O99.21 cannot be reported as written. Where the codes beneath it include an unspecified code, that code applies when the record goes no further; otherwise query for the missing detail.

    ReviewO99.210, O99.211, O99.212, O99.213, O99.214, O99.215

Report the code beneath O99.21 that the documentation supports, not O99.21 itself. Then work the Use Additional Code note, and confirm that code is valid for the date of service on its own page.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
Trimester
Assigned from the documented trimester at the encounter, or the trimester in which the condition developed for inpatient stays (Guidelines I.C.15.a.3).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.

Official instructions as workflow

  • Excludes2 — not part of O99.21(4 notes)

    Coding workflow: The conditions named in this note are not included in O99.21. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareO24, O25, O90.5

    See the official tabular notes · Guidelines I.A.12.b

  • Use Additional Code — after identifying O99.21(2 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with O99.21 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewE66

    See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with the code beneath O99.21?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

ReviewE66

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Don’t confuse O99.21 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of O99.21 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

  • O24— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of diabetes mellitus adds O24; it is not part of this code and both may be reported when both are documented.

    Full comparison: O99.21 vs O24 →

  • O25— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of malnutrition adds O25; it is not part of this code and both may be reported when both are documented.

    Full comparison: O99.21 vs O25 →

  • O90.5— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of postpartum thyroiditis adds O90.5; it is not part of this code and both may be reported when both are documented.

    Full comparison: O99.21 vs O90.5 →

  • O35— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of when the reason for maternal care is that the condition is known or suspected to have affected the fetus adds O35; it is not part of this code and both may be reported when both are documented.

    Full comparison: O99.21 vs O35 →

  • O36— Excludes2 relationship (Informational)

    Distinct conditions — both may be reported.

    A distinct condition — both may be reported when both are documented.

    What moves you there: Documentation of when the reason for maternal care is that the condition is known or suspected to have affected the fetus adds O36; it is not part of this code and both may be reported when both are documented.

    Full comparison: O99.21 vs O36 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Coding context

Guidelines, coding notes, decision aids, relationships (with MS-DRG and CCSR classification), hierarchy, HCC, coverage and the context map: what a coder reaches for after the core. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Code Overview

Obesity complicating pregnancy, childbirth, and the puerperium is a non-billable ICD-10-CM category code (O99.21). A more specific billable subcode must be selected for claims submission.

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

Official Coding Guidelines

Official source data — quoted verbatim from the CMS/NCHS Official Guidelines

Verbatim excerpts from the ICD-10-CM Official Guidelines for Coding and Reporting (CMS/NCHS) that govern this code.

Chapter 4: Endocrine, Nutritional, and Metabolic Diseases (E00 -E89)

b. Obesity The obesity codes in category E66, Overweight and obesity, include codes related to the cause of obesity, such as drug-induced obesity (E66.1), and codes related to effects of obesity, such as code E66.2, Morbid (severe) obesity with alveolar hypoventilation. There are other codes related to obesity in other categories of the classification, such as E88.82, Obesity due to disruption of MC4R pathway; and codes in fifth character subcategory O99.21, Obesity complicating pregnancy, childbirth, and the puerperium.

Verify Before Coding

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-derived relationships — computed from published CMS and AHRQ datasets

Other codes that name O99.21 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 10 Excludes2 notes: O20 — Hemorrhage in early pregnancy (via O99.-), O20-O29 — Other maternal disorders predominantly related to pregnancy (O20-O29) (via O99.-), O21 — Excessive vomiting in pregnancy (via O99.-), O22 — Venous complications and hemorrhoids in pregnancy (via O99.-), O23 — Infections of genitourinary tract in pregnancy (via O99.-), O24 — Diabetes mellitus in pregnancy, childbirth, and the puerperium (via O99.-), O25 — Malnutrition in pregnancy, childbirth and the puerperium (via O99.-), O26 — Maternal care for other conditions predominantly related to pregnancy (via O99.-), O28 — Abnormal findings on antenatal screening of mother (via O99.-), O29 — Complications of anesthesia during pregnancy (via O99.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 1 Code First instruction: E66 — Overweight and obesity.

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

Related Codes

Same Index main term, other category

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

E23.6 — Other disorders of pituitary gland (pituitary), E27.8 — Other specified disorders of adrenal gland (adrenal), E66.01 — Morbid (severe) obesity due to excess calories (severe), E66.09 — Other obesity due to excess calories (exogenous), E66.1 — Drug-induced obesity (drug-induced), E66.2 — Morbid (severe) obesity with alveolar hypoventilation (hypoventilation syndrome), E66.811 — Obesity, class 1 (class, 1), E66.812 — Obesity, class 2 (class, 2), E66.813 — Obesity, class 3 (class, 3), E66.89 — Other obesity not elsewhere classified (familial), E66.9 — Obesity, unspecified, E88.82 — Obesity due to disruption of MC4R pathway (due to, gene mutation, leptin), Z71.3 — Dietary counseling and surveillance (dietary counseling and surveillance)

Contextual Map

Every relationship of O99.21 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.

Run O99.21 with these 9 related codes in Claim Check

Hierarchy

Use Additional Code

  • E66 — Overweight and obesity[Use Additional Code]: “code to identify the type of obesity (E66.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027

Referenced by Excludes2 notes (10)

Referenced by Code First instructions

  • E66 — Overweight and obesity[Code First]: “obesity complicating pregnancy, childbirth and the puerperium, if applicable (O99.21-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027

Nearest codes (40)

Change history

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

Reference

Index terms and tables, published questions and FAQ, every source behind this page with its release and checksum, the date-of-service check and the complete change history.

Common coding questions

MedCoder editorial

Can O99.21 be billed directly?

No. O99.21 (Obesity complicating pregnancy, childbirth, and the puerperium) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

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 FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Coding guidelines Official source data
ICD-10-CM Official Guidelines for Coding and Reporting (FY2027), quoted by section Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) 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-derived 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 editorial 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.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

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. "O99.21 — Obesity complicating pregnancy, childbirth, and the puerperium." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/o99.21-obesity-complicating-pregnancy-childbirth-and-the-puerperium

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Obesity complicating pregnancy, childbirth, and the puerperium

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, 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 O99.21 in its code family, with their registry titles.

View all codes in the O99 family