O90.5 ICD-10-CM Code: Postpartum thyroiditis

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for O90.5 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 O90.5 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for O90.5

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

Before you code O90.5

1. 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 →

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).

Official instructions as workflow

• Excludes2 — not part of O90.5(3 notes)

  Coding workflow: The conditions named in this note are not included in O90.5. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareF53, A34, M83.0

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

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.

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.

• Puerperal, puerperium (complicated by, complications), thyroiditis
• Thyroiditis, postpartum, puerperal

Don’t confuse O90.5 with…

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

The codes most likely to be picked instead of O90.5 — 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.

• O90.9— Specificity relationship (Review)

  Overlapping diagnoses in the same category.

  Overlapping codes in the same category — the documentation decides which is the more specific fit.

  What moves you there: A record that documents no more than “Complication of the puerperium, unspecified” takes O90.9; specificity in the record moves it back here.

  Full comparison: O90.5 vs O90.9 →

• F53— 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 mental and behavioral disorders associated with the puerperium adds F53; it is not part of this code and both may be reported when both are documented.

  Full comparison: O90.5 vs F53 →

• A34— 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 obstetrical tetanus adds A34; it is not part of this code and both may be reported when both are documented.

  Full comparison: O90.5 vs A34 →

• M83.0— 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 puerperal osteomalacia adds M83.0; it is not part of this code and both may be reported when both are documented.

  Full comparison: O90.5 vs M83.0 →

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.

Verify Before Coding

• Age-restricted: the Medicare Code Editor lists this as a maternity (age 9-64) diagnosis; other ages are presumed incorrect.

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

Other codes that name O90.5 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 1 Excludes1 note: E06 — Thyroiditis.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 1 Excludes2 note: O99.2 — Endocrine, nutritional and metabolic diseases complicating pregnancy, childbirth and the puerperium.

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

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 2 MS-DRGs: DRG 769 (MDC 14), DRG 776 (MDC 14).

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

Clinical classification (AHRQ CCSR):PRG027 — Complications specified during the puerperium (default); END001 — Thyroid disorders.

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 categories (Complications specified during the puerperium, Thyroid disorders).

O89.5 — Other complications of spinal and epidural anesthesia during the puerperium, O89.6 — Failed or difficult intubation for anesthesia during the puerperium, O89.8 — Other complications of anesthesia during the puerperium, O89.9 — Complication of anesthesia during the puerperium, unspecified, O90.0 — Disruption of cesarean delivery wound, O90.1 — Disruption of perineal obstetric wound, O90.2 — Hematoma of obstetric wound, O90.4 — Postpartum acute kidney failure, O90.41 — Hepatorenal syndrome following labor and delivery, O90.49 — Other postpartum acute kidney failure, O90.6 — Postpartum mood disturbance, O90.81 — Anemia of the puerperium, O90.89 — Other complications of the puerperium, not elsewhere classified, O90.9 — Complication of the puerperium, unspecified, O91.02 — Infection of nipple associated with the puerperium, O91.03 — Infection of nipple associated with lactation, O91.12 — Abscess of breast associated with the puerperium, O91.13 — Abscess of breast associated with lactation, O91.22 — Nonpurulent mastitis associated with the puerperium, O91.23 — Nonpurulent mastitis associated with lactation, +168 more

Same Index main term, other category

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

O86.4 — Pyrexia of unknown origin following delivery (fever), O86.81 — Puerperal septic thrombophlebitis (septic thrombophlebitis), O86.89 — Other specified puerperal infections (lymphangitis), O87.0 — Superficial thrombophlebitis in the puerperium (phlebitis), O87.1 — Deep phlebothrombosis in the puerperium (milk leg), O87.2 — Hemorrhoids in the puerperium (hemorrhoids), O87.4 — Varicose veins of lower extremity in the puerperium (varicose veins), O87.8 — Other venous complications in the puerperium (varicose veins, vulva or perineum), O87.9 — Venous complication in the puerperium, unspecified (venous), O89.8 — Other complications of anesthesia during the puerperium (anesthetic death), O91.02 — Infection of nipple associated with the puerperium (thelitis), O91.03 — Infection of nipple associated with lactation (thelitis, associated with lactation), O91.12 — Abscess of breast associated with the puerperium (fistula, breast), O91.13 — Abscess of breast associated with lactation (fistula, breast, associated with lactation), O91.22 — Nonpurulent mastitis associated with the puerperium (mammitis), O91.23 — Nonpurulent mastitis associated with lactation (mastitis, associated with lactation), O92.02 — Retracted nipple associated with the puerperium (retracted nipple), O92.12 — Cracked nipple associated with the puerperium (fissure, nipple), O92.13 — Cracked nipple associated with lactation (fissure, nipple, associated with lactation), O92.29 — Other disorders of breast associated with pregnancy and the puerperium (induration breast), +78 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Lipid Panel, Thyroid Stimulating Hormone (TSH)

Contextual Map

Every relationship of O90.5 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 O90.5 with these 2 related codes in Claim Check

Hierarchy

• O00-O9A — Chapter 15: Pregnancy, Childbirth and the Puerperium (O00-O9A) (O00-O9A)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O85-O92 — Complications predominantly related to the puerperium[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

• E06 — Thyroiditis[Excludes1]: “postpartum thyroiditis (O90.5)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes

• O99.2 — Endocrine, nutritional and metabolic diseases complicating pregnancy, childbirth and the puerperium[Excludes2]: “postpartum thyroiditis (O90.5)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• PRG027 — Complications specified during the puerperium[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)
• END001 — Thyroid disorders[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• DRG 769 — POSTPARTUM AND POST ABORTION DIAGNOSES WITH O.R. PROCEDURES[MS-DRG]: “POSTPARTUM AND POST ABORTION DIAGNOSES WITH O.R. PROCEDURES (MDC 14)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 776 — POSTPARTUM AND POST ABORTION DIAGNOSES WITHOUT O.R. PROCEDURES[MS-DRG]: “POSTPARTUM AND POST ABORTION DIAGNOSES WITHOUT O.R. PROCEDURES (MDC 14)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 14 — Pregnancy, Childbirth and the Puerperium[MDC crossing]: “Pregnancy, Childbirth and the Puerperium — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 94 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Puerperal, puerperium (complicated by, complications), thyroiditis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Thyroiditis, postpartum, puerperal[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (13)

• O90 — Complications of the puerperium, not elsewhere classified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O90.0 — Disruption of cesarean delivery wound[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O90.1 — Disruption of perineal obstetric wound[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O90.2 — Hematoma of obstetric wound[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O90.3 — Peripartum cardiomyopathy[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O90.4 — Postpartum acute kidney failure[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O90.41 — Hepatorenal syndrome following labor and delivery[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O90.49 — Other postpartum acute kidney failure[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 5 more

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

Nearest Codes in This Family

Official ICD-10-CM classifications closest to O90.5 in its code family, with their registry titles.

• O90.2 — Hematoma of obstetric wound
• O90.3 — Peripartum cardiomyopathy
• O90.4 — Postpartum acute kidney failure
• O90.41 — Hepatorenal syndrome following labor and delivery
• O90.49 — Other postpartum acute kidney failure
• O90.6 — Postpartum mood disturbance
• O90.8 — Other complications of the puerperium, not elsewhere classified
• O90.81 — Anemia of the puerperium
• O90.89 — Other complications of the puerperium, not elsewhere classified
• O90.9 — Complication of the puerperium, unspecified

View all codes in the O90 family