O12.12 ICD-10-CM Code: Gestational proteinuria, second trimester

Coder workflow for O12.12

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

Before you code O12.12

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).

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 O12.12 with…

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

The codes most likely to be picked instead of O12.12 — 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.

• O12.10— 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 “Gestational proteinuria, unspecified trimester” takes O12.10; specificity in the record moves it back here.

  Full comparison: O12.12 vs O12.10 →

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.
• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

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 O12.12 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: R80 — Proteinuria (via O12.1.-).

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: O99.4 — Diseases of the circulatory system complicating pregnancy, childbirth and the puerperium (via O12.-).

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: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 20 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 6 MS-DRGs: DRG 817 (MDC 14), DRG 818 (MDC 14), DRG 819 (MDC 14), DRG 831 (MDC 14), DRG 832 (MDC 14), DRG 833 (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):PRG028 — Other specified complications in pregnancy (default); GEN010 — Proteinuria.

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 process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

O11.5 — Pre-existing hypertension with pre-eclampsia, complicating the puerperium, O12.05 — Gestational edema, complicating the puerperium, O12.11 — Gestational proteinuria, first trimester, O12.13 — Gestational proteinuria, third trimester, O12.15 — Gestational proteinuria, complicating the puerperium, O12.21 — Gestational edema with proteinuria, first trimester, O12.22 — Gestational edema with proteinuria, second trimester, O12.23 — Gestational edema with proteinuria, third trimester, O12.25 — Gestational edema with proteinuria, complicating the puerperium, O13.5 — Gestational [pregnancy-induced] hypertension without significant proteinuria, complicating the puerperium, O14.05 — Mild to moderate pre-eclampsia, complicating the puerperium, O14.15 — Severe pre-eclampsia, complicating the puerperium, O14.25 — HELLP syndrome, complicating the puerperium, O14.95 — Unspecified pre-eclampsia, complicating the puerperium, O16.5 — Unspecified maternal hypertension, complicating the puerperium, O26.831 — Pregnancy related renal disease, first trimester, O26.832 — Pregnancy related renal disease, second trimester, O26.833 — Pregnancy related renal disease, third trimester, O90.89 — Other complications of the puerperium, not elsewhere classified

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical categories (Other specified complications in pregnancy, Proteinuria).

N06.3 — Isolated proteinuria with diffuse mesangial proliferative glomerulonephritis, N06.4 — Isolated proteinuria with diffuse endocapillary proliferative glomerulonephritis, N06.5 — Isolated proteinuria with diffuse mesangiocapillary glomerulonephritis, N06.6 — Isolated proteinuria with dense deposit disease, N06.7 — Isolated proteinuria with diffuse crescentic glomerulonephritis, N06.8 — Isolated proteinuria with other morphologic lesion, N06.9 — Isolated proteinuria with unspecified morphologic lesion, N06.A — Isolated proteinuria with C3 glomerulonephritis, O12.10 — Gestational proteinuria, unspecified trimester, O12.11 — Gestational proteinuria, first trimester, O12.13 — Gestational proteinuria, third trimester, O12.14 — Gestational proteinuria, complicating childbirth, O12.15 — Gestational proteinuria, complicating the puerperium, O12.20 — Gestational edema with proteinuria, unspecified trimester, O12.21 — Gestational edema with proteinuria, first trimester, O12.22 — Gestational edema with proteinuria, second trimester, O12.23 — Gestational edema with proteinuria, third trimester, O12.24 — Gestational edema with proteinuria, complicating childbirth, O12.25 — Gestational edema with proteinuria, complicating the puerperium, R80.0 — Isolated proteinuria, +323 more

Same Index main term, other category

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

N06.0 — Isolated proteinuria with minor glomerular abnormality (isolated, with glomerular lesion, minimal change), N06.1 — Isolated proteinuria with focal and segmental glomerular lesions (isolated, with glomerular lesion, focal and segmental hyalinosis or sclerosis), N06.20 — Isolated proteinuria with diffuse membranous glomerulonephritis, unspecified (isolated, with glomerular lesion, membranous), N06.29 — Other isolated proteinuria with diffuse membranous glomerulonephritis (isolated, with glomerular lesion, membranous, with diffuse membranous glomerulonephritis), N06.3 — Isolated proteinuria with diffuse mesangial proliferative glomerulonephritis (isolated, with glomerular lesion, mesangial proliferative), N06.4 — Isolated proteinuria with diffuse endocapillary proliferative glomerulonephritis (isolated, with glomerular lesion, diffuse, endocapillary proliferative glomerulonephritis), N06.5 — Isolated proteinuria with diffuse mesangiocapillary glomerulonephritis (isolated, with glomerular lesion, diffuse, mesangiocapillary glomerulonephritis), N06.6 — Isolated proteinuria with dense deposit disease (isolated, with glomerular lesion, dense deposit disease), N06.7 — Isolated proteinuria with diffuse crescentic glomerulonephritis (isolated, with glomerular lesion, diffuse, crescentic glomerulonephritis), N06.8 — Isolated proteinuria with other morphologic lesion (isolated, with glomerular lesion, specified pathology NEC), N06.9 — Isolated proteinuria with unspecified morphologic lesion (isolated, with glomerular lesion), N06.A — Isolated proteinuria with C3 glomerulonephritis (isolated, with glomerular lesion, C3, glomerulopathy), R80.0 — Isolated proteinuria (isolated), R80.1 — Persistent proteinuria, unspecified (persistent), R80.2 — Orthostatic proteinuria, unspecified (postural), R80.3 — Bence Jones proteinuria (Bence Jones), R80.8 — Other proteinuria (specified type NEC), R80.9 — Proteinuria, unspecified

Contextual Map

Every relationship of O12.12 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 O12.12 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
• O10-O16 — Edema, proteinuria and hypertensive disorders in pregnancy, childbirth and the puerperium[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

• R80 — Proteinuria[Excludes1](via O12.1.-): “gestational proteinuria (O12.1-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes

• O99.4 — Diseases of the circulatory system complicating pregnancy, childbirth and the puerperium[Excludes2](via O12.-): “hypertensive disorders (O10-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• PRG028 — Other specified complications in pregnancy[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)
• GEN010 — Proteinuria[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 817 — OTHER ANTEPARTUM DIAGNOSES WITH O.R. PROCEDURES WITH MCC[MS-DRG]: “OTHER ANTEPARTUM DIAGNOSES WITH O.R. PROCEDURES WITH MCC (MDC 14)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 818 — OTHER ANTEPARTUM DIAGNOSES WITH O.R. PROCEDURES WITH CC[MS-DRG]: “OTHER ANTEPARTUM DIAGNOSES WITH O.R. PROCEDURES WITH CC (MDC 14)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 819 — OTHER ANTEPARTUM DIAGNOSES WITH O.R. PROCEDURES WITHOUT CC/MCC[MS-DRG]: “OTHER ANTEPARTUM DIAGNOSES WITH O.R. PROCEDURES WITHOUT CC/MCC (MDC 14)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 831 — OTHER ANTEPARTUM DIAGNOSES WITHOUT O.R. PROCEDURES WITH MCC[MS-DRG]: “OTHER ANTEPARTUM DIAGNOSES WITHOUT O.R. PROCEDURES WITH MCC (MDC 14)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 832 — OTHER ANTEPARTUM DIAGNOSES WITHOUT O.R. PROCEDURES WITH CC[MS-DRG]: “OTHER ANTEPARTUM DIAGNOSES WITHOUT O.R. PROCEDURES WITH CC (MDC 14)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 833 — OTHER ANTEPARTUM DIAGNOSES WITHOUT O.R. PROCEDURES WITHOUT CC/MCC[MS-DRG]: “OTHER ANTEPARTUM DIAGNOSES WITHOUT O.R. PROCEDURES WITHOUT CC/MCC (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

Nearest codes (21)

• O12 — Gestational [pregnancy-induced] edema and proteinuria without hypertension[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O12.0 — Gestational edema[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O12.00 — Gestational edema, unspecified trimester[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O12.01 — Gestational edema, first trimester[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O12.02 — Gestational edema, second trimester[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O12.03 — Gestational edema, third trimester[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O12.04 — Gestational edema, complicating childbirth[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O12.05 — Gestational edema, complicating the puerperium[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 13 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 O12.12 in its code family, with their registry titles.

• O12.04 — Gestational edema, complicating childbirth
• O12.05 — Gestational edema, complicating the puerperium
• O12.1 — Gestational proteinuria
• O12.10 — Gestational proteinuria, unspecified trimester
• O12.11 — Gestational proteinuria, first trimester
• O12.13 — Gestational proteinuria, third trimester
• O12.14 — Gestational proteinuria, complicating childbirth
• O12.15 — Gestational proteinuria, complicating the puerperium
• O12.2 — Gestational edema with proteinuria
• O12.20 — Gestational edema with proteinuria, unspecified trimester

View all codes in the O12 family