O14.12 ICD-10-CM Code: Severe pre-eclampsia, second trimester

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for O14.12 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 O14.12 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for O14.12

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

Before you code O14.12

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 →

2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with O14.12. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

   See the official tabular notes

Choose the right path

1. Does the documentation support a condition named in O14.12’s Excludes1 note?
   Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
   No → Continue.

   ReviewO14.2, O11

Consider O14.12. Then confirm the code is valid for the date of service in the Verify section.

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).

Severity

Mild, moderate or severe as the provider states it; severity is not inferred from the clinical picture.

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

• Excludes1 — check before selecting O14.12(2 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with O14.12: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareO14.2, O11

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

Coding decision scenarios

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

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.

Official Coding Guidelines

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

Don’t confuse O14.12 with…

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

The codes most likely to be picked instead of O14.12 — 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.

• O14.2— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of HELLP syndrome moves the case to O14.2; the two are not reported together unless documented as unrelated.

  Full comparison: O14.12 vs O14.2 →

• O11— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of pre-existing hypertension with pre-eclampsia moves the case to O11; the two are not reported together unless documented as unrelated.

  Full comparison: O14.12 vs O11 →

• O14.10— 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 “Severe pre-eclampsia, unspecified trimester” takes O14.10; specificity in the record moves it back here.

  Full comparison: O14.12 vs O14.10 →

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.
• MCC 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 O14.12 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: I10 — Essential (primary) hypertension (via O14.-).

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

Referenced by 8 Excludes2 notes across 2 chapters: I10-I1A — Hypertensive diseases (I10-I1A) (via O14.-), I11 — Hypertensive heart disease (via O14.-), I12 — Hypertensive chronic kidney disease (via O14.-), I13 — Hypertensive heart and chronic kidney disease (via O14.-), I15 — Secondary hypertension (via O14.-), I16 — Hypertensive crisis (via O14.-), I1A — Other hypertension (via O14.-), O99.4 — Diseases of the circulatory system complicating pregnancy, childbirth and the puerperium (via O14.-).

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: MCC — Major 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 298 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):PRG020 — Hypertension and hypertensive-related conditions complicating pregnancy; childbirth; and the puerperium (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 process (MS-DRG)

Acts as MCC — 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.

O13.3 — Gestational [pregnancy-induced] hypertension without significant proteinuria, third trimester, O13.4 — Gestational [pregnancy-induced] hypertension without significant proteinuria, complicating childbirth, O13.5 — Gestational [pregnancy-induced] hypertension without significant proteinuria, complicating the puerperium, O13.9 — Gestational [pregnancy-induced] hypertension without significant proteinuria, unspecified trimester, O14.00 — Mild to moderate pre-eclampsia, unspecified trimester, O14.02 — Mild to moderate pre-eclampsia, second trimester, O14.03 — Mild to moderate pre-eclampsia, third trimester, O14.04 — Mild to moderate pre-eclampsia, complicating childbirth, O14.05 — Mild to moderate pre-eclampsia, complicating the puerperium, O14.10 — Severe pre-eclampsia, unspecified trimester, O14.13 — Severe pre-eclampsia, third trimester, O14.14 — Severe pre-eclampsia complicating childbirth, O14.15 — Severe pre-eclampsia, complicating the puerperium, O14.20 — HELLP syndrome (HELLP), unspecified trimester, O14.22 — HELLP syndrome (HELLP), second trimester, O14.23 — HELLP syndrome (HELLP), third trimester, O14.24 — HELLP syndrome, complicating childbirth, O14.25 — HELLP syndrome, complicating the puerperium, O14.90 — Unspecified pre-eclampsia, unspecified trimester, O14.92 — Unspecified pre-eclampsia, second trimester, +277 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Hypertension and hypertensive-related conditions complicating pregnancy; childbirth; and the puerperium).

O13.3 — Gestational [pregnancy-induced] hypertension without significant proteinuria, third trimester, O13.4 — Gestational [pregnancy-induced] hypertension without significant proteinuria, complicating childbirth, O13.5 — Gestational [pregnancy-induced] hypertension without significant proteinuria, complicating the puerperium, O13.9 — Gestational [pregnancy-induced] hypertension without significant proteinuria, unspecified trimester, O14.00 — Mild to moderate pre-eclampsia, unspecified trimester, O14.02 — Mild to moderate pre-eclampsia, second trimester, O14.03 — Mild to moderate pre-eclampsia, third trimester, O14.04 — Mild to moderate pre-eclampsia, complicating childbirth, O14.05 — Mild to moderate pre-eclampsia, complicating the puerperium, O14.10 — Severe pre-eclampsia, unspecified trimester, O14.13 — Severe pre-eclampsia, third trimester, O14.14 — Severe pre-eclampsia complicating childbirth, O14.15 — Severe pre-eclampsia, complicating the puerperium, O14.20 — HELLP syndrome (HELLP), unspecified trimester, O14.22 — HELLP syndrome (HELLP), second trimester, O14.23 — HELLP syndrome (HELLP), third trimester, O14.24 — HELLP syndrome, complicating childbirth, O14.25 — HELLP syndrome, complicating the puerperium, O14.90 — Unspecified pre-eclampsia, unspecified trimester, O14.92 — Unspecified pre-eclampsia, second trimester, +59 more

Same Index main term, other category

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

O10.22 — Pre-existing hypertensive chronic kidney disease complicating childbirth (complicating, childbirth, pre-existing, with, renal disease), O10.23 — Pre-existing hypertensive chronic kidney disease complicating the puerperium (complicating, puerperium, pre-existing, pre-existing, with, renal disease), O10.31 — Pre-existing hypertensive heart and chronic kidney disease complicating pregnancy (complicating, pregnancy, pre-existing, with, renal disease, with heart disease), O10.32 — Pre-existing hypertensive heart and chronic kidney disease complicating childbirth (complicating, childbirth, pre-existing, with, heart disease, with renal disease), O10.33 — Pre-existing hypertensive heart and chronic kidney disease complicating the puerperium (complicating, puerperium, pre-existing, pre-existing, with, renal disease, with heart disease), O10.41 — Pre-existing secondary hypertension complicating pregnancy (complicating, pregnancy, pre-existing, secondary), O10.42 — Pre-existing secondary hypertension complicating childbirth (complicating, childbirth, secondary), O10.43 — Pre-existing secondary hypertension complicating the puerperium (complicating, puerperium, pre-existing, secondary), O10.91 — Unspecified pre-existing hypertension complicating pregnancy (complicating, pregnancy, pre-existing), O10.92 — Unspecified pre-existing hypertension complicating childbirth (complicating, childbirth, pre-existing), O11.4 — Pre-existing hypertension with pre-eclampsia, complicating childbirth (complicating, childbirth, pre-existing, with, pre-eclampsia), O11.5 — Pre-existing hypertension with pre-eclampsia, complicating the puerperium (complicating, puerperium, pre-existing, pre-existing, with, pre-eclampsia), O13.4 — Gestational [pregnancy-induced] hypertension without significant proteinuria, complicating childbirth (gestational, complicating, delivery), O13.5 — Gestational [pregnancy-induced] hypertension without significant proteinuria, complicating the puerperium (gestational, complicating, puerperium), O13.9 — Gestational [pregnancy-induced] hypertension without significant proteinuria, unspecified trimester (complicating, puerperium, pre-existing, pregnancy-induced), O16.4 — Unspecified maternal hypertension, complicating childbirth (complicating, childbirth), O16.5 — Unspecified maternal hypertension, complicating the puerperium (complicating, puerperium, pre-existing), P29.2 — Neonatal hypertension (newborn), P29.30 — Pulmonary hypertension of newborn (newborn, pulmonary), R03.0 — Elevated blood-pressure reading, without diagnosis of hypertension (transient), +51 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.

Gamma-glutamyl Transferase (GGT) Test, Partial Thromboplastin Time (PTT) Test, Pregnancy Test, Prothrombin Time Test and INR (PT/INR)

Contextual Map

Every relationship of O14.12 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 O14.12 with these 9 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

• I10 — Essential (primary) hypertension[Excludes1](via O14.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes

• I10-I1A — Hypertensive diseases (I10-I1A)[Excludes2](via O14.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I11 — Hypertensive heart disease[Excludes2](via O14.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I12 — Hypertensive chronic kidney disease[Excludes2](via O14.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I13 — Hypertensive heart and chronic kidney disease[Excludes2](via O14.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I15 — Secondary hypertension[Excludes2](via O14.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I16 — Hypertensive crisis[Excludes2](via O14.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• I1A — Other hypertension[Excludes2](via O14.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• O99.4 — Diseases of the circulatory system complicating pregnancy, childbirth and the puerperium[Excludes2](via O14.-): “hypertensive disorders (O10-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• PRG020 — Hypertension and hypertensive-related conditions complicating pregnancy; childbirth; and the puerperium[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• MCC — Major Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (MCC).”— 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 (24)

• O14 — Pre-eclampsia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O14.0 — Mild to moderate pre-eclampsia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O14.00 — Mild to moderate pre-eclampsia, unspecified trimester[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O14.02 — Mild to moderate pre-eclampsia, second trimester[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O14.03 — Mild to moderate pre-eclampsia, third trimester[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O14.04 — Mild to moderate pre-eclampsia, complicating childbirth[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O14.05 — Mild to moderate pre-eclampsia, complicating the puerperium[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• O14.1 — Severe pre-eclampsia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 16 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

Coding guidelines Official source data

ICD-10-CM Official Guidelines for Coding and Reporting (FY2026), quoted by section 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 O14.12 in its code family, with their registry titles.

• O14.03 — Mild to moderate pre-eclampsia, third trimester
• O14.04 — Mild to moderate pre-eclampsia, complicating childbirth
• O14.05 — Mild to moderate pre-eclampsia, complicating the puerperium
• O14.1 — Severe pre-eclampsia
• O14.10 — Severe pre-eclampsia, unspecified trimester
• O14.13 — Severe pre-eclampsia, third trimester
• O14.14 — Severe pre-eclampsia complicating childbirth
• O14.15 — Severe pre-eclampsia, complicating the puerperium
• O14.2 — HELLP syndrome
• O14.20 — HELLP syndrome (HELLP), unspecified trimester

View all codes in the O14 family