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O90.5 vs O99.28

O90.5 (Postpartum thyroiditis) compared with O99.28 (Other endocrine, nutritional and metabolic diseases complicating pregnancy, childbirth and the puerperium), from the official CMS tabular data.

Summary

These codes can be reported together when both conditions are documented, because O99.28 lists O90.5 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named and billing status.O90.5 is “Postpartum thyroiditis”; O99.28 is “Other endocrine, nutritional and metabolic diseases complicating pregnancy, childbirth and the puerperium”. O99.28 is a non-billable header; O90.5 is billable.

Registry fact

Can these codes be reported together?

Yes, when both are documented.O99.28 lists O90.5 under Excludes2: “postpartum thyroiditis (O90.5)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code.

Official rule

Is there an Excludes2 relationship?

Yes.O99.28’s tabular entry: “postpartum thyroiditis (O90.5)”. The note covers O90.5.

Official ruleGuide: Excludes1 vs Excludes2

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Is one a parent or header code?

One is a header.O99.28 is a non-billable header, but O90.5 is not one of its subdivisions.

Registry fact

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Informational

Excludes2 relationship

O99.28
Other endocrine, nutritional and metabolic diseases complicating pregnancy, childbirth and the puerperium
↔
O90.5
Postpartum thyroiditis

What we found

Yes, when both are documented.O99.28 carries an Excludes2 note covering O90.5: “postpartum thyroiditis (O90.5)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

    ICD-10-CM Official Guidelines FY2026

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

O90.5Postpartum thyroiditisO99.28Other endocrine, nutritional and metabolic diseases complicating pregnancy, childbirth and the puerperium
Billing statusBillableNon-billable header

Report instead: O99.280, O99.281, O99.282, O99.283, O99.284

ClassificationO00-O9A — Pregnancy, Childbirth and the Puerperium (O00-O9A)O00-O9A — Pregnancy, Childbirth and the Puerperium (O00-O9A)
DefinitionPostpartum thyroiditis is a billable ICD-10-CM diagnosis code (O90.5).Other endocrine, nutritional and metabolic diseases complicating pregnancy, childbirth and the puerperium is a non-billable ICD-10-CM category code (O99.28).
Includes—
conditions which complicate the pregnant state, are aggravated by the pregnancy or are a main reason for obstetric care
Excludes2
mental and behavioral disorders associated with the puerperium (F53.-)
obstetrical tetanus (A34)
puerperal osteomalacia (M83.0)
diabetes mellitus (O24.-)
malnutrition (O25.-)
postpartum thyroiditis (O90.5)
when the reason for maternal care is that the condition is known or suspected to have affected the fetus (O35-O36)
Use additional code—
code to identify specific condition

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on.

Edit this comparisonCheck a whole claim

Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources