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O10.019 ICD-10-CM Code: Pre-existing essential hypertension complicating pregnancy, unspecified trimester

Compare with another code for O10.019Check this code on a claim

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
1 inclusion term · 1 Excludes2

Billable · FY2027A valid, specific ICD-10-CM code, reportable for dates of service in FY2027.

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.

Excludes2from O10Not included here; may be reported together
  • pre-existing hypertension with superimposed pre-eclampsia complicating pregnancy, childbirth and the puerperium (O11.-)
Includesfrom O10What O10 covers
  • pre-existing hypertension with pre-existing proteinuria complicating pregnancy, childbirth and the puerperium

Where it sits Source: CMS/NCHS

Under:Chapter 15: Pregnancy, Childbirth and the PuerperiumO10-O16 Edema, proteinuria and hypertensive disorders in pregnancy, childbirth and the puerperiumO10 Pre-existing hypertension complicating pregnancy, childbirth and the puerperiumO10.0 Pre-existing essential hypertension complicating pregnancy, childbirth and the puerperiumO10.01 Pre-existing essential hypertension complicating pregnancy

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

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 817 — OTHER ANTEPARTUM DIAGNOSES WITH O.R. PROCEDURES WITH MCC (MDC 14)
  • MS-DRG 818 — OTHER ANTEPARTUM DIAGNOSES WITH O.R. PROCEDURES WITH CC (MDC 14)
  • MS-DRG 819 — OTHER ANTEPARTUM DIAGNOSES WITH O.R. PROCEDURES WITHOUT CC/MCC (MDC 14)
  • MS-DRG 831 — OTHER ANTEPARTUM DIAGNOSES WITHOUT O.R. PROCEDURES WITH MCC (MDC 14)
  • MS-DRG 832 — OTHER ANTEPARTUM DIAGNOSES WITHOUT O.R. PROCEDURES WITH CC (MDC 14)
  • MS-DRG 833 — OTHER ANTEPARTUM DIAGNOSES WITHOUT O.R. PROCEDURES WITHOUT CC/MCC (MDC 14)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for O10.019 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 O10.019 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.

  • pre-existing hypertension with pre-existing proteinuria complicating pregnancy, childbirth and the puerperium

Source: inherited from O10

Excludes2 — Not Included Here

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

  • pre-existing hypertension with superimposed pre-eclampsia complicating pregnancy, childbirth and the puerperium (O11.-) Compare O10.019 vs O11 →

Source: inherited from O10

Coder workflow for O10.019

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

Before you code O10.019

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, O10.019 may be the appropriate code. Check the record for detail that supports a more specific sibling — in this subcategory the siblings differ by trimester. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).

    ReviewO10.011, O10.012, O10.013

    See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

  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 record document the detail a more specific sibling code needs?
    Yes → Review the specific siblings in this subcategory.
    No → Continue — O10.019 is appropriate when the documentation goes no further.

    ReviewO10.011, O10.012, O10.013

Consider O10.019. 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).
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).
Any detail beyond this code’s title
What the record states that a more specific code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

  • Excludes2 — not part of O10.019(1 note)

    Coding workflow: The conditions named in this note are not included in O10.019. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareO11

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

Coding decision scenarios

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

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the specific siblings in this subcategory and what each requires the record to state.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

ReviewO10.011, O10.012, O10.013

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 O10.019 with…

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

The codes most likely to be picked instead of O10.019 — 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.

  • O11— 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 pre-existing hypertension with superimposed pre-eclampsia complicating pregnancy, childbirth and the puerperium adds O11; it is not part of this code and both may be reported when both are documented.

    Full comparison: O10.019 vs O11 →

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

Pre-existing essential hypertension complicating pregnancy, unspecified trimester is a billable ICD-10-CM diagnosis code (O10.019).

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 15: Pregnancy, Childbirth, and the Puerperium (O00-O9A)

d. Pre-existing hypertension in pregnancy Category O10, Pre-existing hypertension complicating pregnancy, childbirth and the puerperium, includes codes for hypertensive heart and hypertensive chronic kidney disease. When assigning one of the O10 codes that includes hypertensive heart disease or hypertensive chronic kidney disease, it is necessary to add a secondary code from the appropriate hypertension category to specify the type of heart failure or chronic kidney disease.

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-derived relationships — computed from published CMS and AHRQ datasets

Other codes that name O10.019 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 O10.-).

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 O10.-), I11 — Hypertensive heart disease (via O10.-), I12 — Hypertensive chronic kidney disease (via O10.-), I13 — Hypertensive heart and chronic kidney disease (via O10.-), I15 — Secondary hypertension (via O10.-), I16 — Hypertensive crisis (via O10.-), I1A — Other hypertension (via O10.-), O99.4 — Diseases of the circulatory system complicating pregnancy, childbirth and the puerperium (via O10.-).

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

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 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 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); CIR007 — Essential hypertension.

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 (Hypertension and hypertensive-related conditions complicating pregnancy; childbirth; and the puerperium, Essential hypertension).

I10 — Essential (primary) hypertension, O10.011 — Pre-existing essential hypertension complicating pregnancy, first trimester, O10.012 — Pre-existing essential hypertension complicating pregnancy, second trimester, O10.013 — Pre-existing essential hypertension complicating pregnancy, third trimester, O10.02 — Pre-existing essential hypertension complicating childbirth, O10.03 — Pre-existing essential hypertension complicating the puerperium, O10.111 — Pre-existing hypertensive heart disease complicating pregnancy, first trimester, O10.112 — Pre-existing hypertensive heart disease complicating pregnancy, second trimester, O10.113 — Pre-existing hypertensive heart disease complicating pregnancy, third trimester, O10.119 — Pre-existing hypertensive heart disease complicating pregnancy, unspecified trimester, O10.12 — Pre-existing hypertensive heart disease complicating childbirth, O10.13 — Pre-existing hypertensive heart disease complicating the puerperium, O10.211 — Pre-existing hypertensive chronic kidney disease complicating pregnancy, first trimester, O10.212 — Pre-existing hypertensive chronic kidney disease complicating pregnancy, second trimester, O10.213 — Pre-existing hypertensive chronic kidney disease complicating pregnancy, third trimester, O10.219 — Pre-existing hypertensive chronic kidney disease complicating pregnancy, unspecified trimester, O10.22 — Pre-existing hypertensive chronic kidney disease complicating childbirth, O10.23 — Pre-existing hypertensive chronic kidney disease complicating the puerperium, O10.311 — Pre-existing hypertensive heart and chronic kidney disease complicating pregnancy, first trimester, O10.312 — Pre-existing hypertensive heart and chronic kidney disease complicating pregnancy, second trimester, +60 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.

I87.30 — Chronic venous hypertension (idiopathic) without complications (venous, idiopathic, asymptomatic), I87.309 — Chronic venous hypertension (idiopathic) without complications of unspecified lower extremity (venous, idiopathic), I87.31 — Chronic venous hypertension (idiopathic) with ulcer (venous, idiopathic, with, ulcer), I87.32 — Chronic venous hypertension (idiopathic) with inflammation (venous, idiopathic, with, inflammation), I87.33 — Chronic venous hypertension (idiopathic) with ulcer and inflammation (venous, idiopathic, with, inflammation, with ulcer), I87.39 — Chronic venous hypertension (idiopathic) with other complications (venous, idiopathic, with, specified complication NEC), I97.3 — Postprocedural hypertension (postoperative), K31.89 — Other diseases of stomach and duodenum (portal, gastropathy), K76.6 — Portal hypertension (portal), K86.1 — Other chronic pancreatitis (pancreatic duct - code to underlying condition, with chronic pancreatitis), 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), O14.0 — Mild to moderate pre-eclampsia (complicating, pregnancy, gestational, with proteinuria, mild pre-eclampsia), O14.1 — Severe pre-eclampsia (complicating, pregnancy, gestational, with proteinuria, severe pre-eclampsia), O14.2 — HELLP syndrome (complicating, pregnancy, gestational, with proteinuria, severe pre-eclampsia, with hemolysis, elevated liver enzymes and low platelet count), O14.9 — Unspecified pre-eclampsia (complicating, pregnancy, with edema), O16.4 — Unspecified maternal hypertension, complicating childbirth (complicating, childbirth), +38 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.

Partial Thromboplastin Time (PTT) Test, Prothrombin Time Test and INR (PT/INR)

Contextual Map

Every relationship of O10.019 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 O10.019 with these 9 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

  • I10 — Essential (primary) hypertension[Excludes1](via O10.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027

Referenced by Excludes2 notes

  • I10-I1A — Hypertensive diseases (I10-I1A)[Excludes2](via O10.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027
  • I11 — Hypertensive heart disease[Excludes2](via O10.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027
  • I12 — Hypertensive chronic kidney disease[Excludes2](via O10.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027
  • I13 — Hypertensive heart and chronic kidney disease[Excludes2](via O10.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027
  • I15 — Secondary hypertension[Excludes2](via O10.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027
  • I16 — Hypertensive crisis[Excludes2](via O10.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027
  • I1A — Other hypertension[Excludes2](via O10.-): “hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027
  • O99.4 — Diseases of the circulatory system complicating pregnancy, childbirth and the puerperium[Excludes2](via O10.-): “hypertensive disorders (O10-O16)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2027

Clinical classification (CCSR)

MS-DRG Grouper

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 · 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.

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
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 — v44 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. "O10.019 — Pre-existing essential hypertension complicating pregnancy, unspecified trimester." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/o10.019-pre-existing-essential-hypertension-complicating-pregnancy-unspecified-trimester

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Pre-existing essential hypertension complicating pregnancy, unspecified trimester

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 O10.019 in its code family, with their registry titles.

View all codes in the O10 family