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O99.35 ICD-10-CM Code: Diseases of the nervous system complicating pregnancy, childbirth, and the puerperium

Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.

Coding at a Glance

Tabular directives
2 inclusion terms · 2 Excludes2 · 1 use-additional code

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for O99.35 in the official ICD-10-CM tabular list, quoted as published.

Notes without a marker are published on O99.35 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.

  • conditions which complicate the pregnant state, are aggravated by the pregnancy or are a main reason for obstetric care

Source: inherited from O99

Inclusion Terms

Alternative terms the tabular list files under this code.

  • Conditions in G00-G99

Excludes2 — Not Included Here

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

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code to identify specific condition

Source: inherited from O99

Coder workflow for O99.35

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

Before you code O99.35

  1. O99.35 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

    ReviewO99.350, O99.351, O99.352, O99.353, O99.354, O99.355

    See the relationships section · Guide: How to choose an ICD-10-CM code →

  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 documentation support one of the more specific codes beneath O99.35?
    Yes → Select that code and continue the checks below on its own page.
    No → O99.35 cannot be reported as written; query for the specificity its subcategory needs.

    ReviewO99.350, O99.351, O99.352, O99.353, O99.354, O99.355

Consider O99.35. Then work the Use Additional Code note, and 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).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.

Official instructions as workflow

  • Excludes2 — not part of O99.35(2 notes)

    Coding workflow: The conditions named in this note are not included in O99.35. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

    CompareO26.8

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

  • Use Additional Code — after identifying O99.35(1 note)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with O99.35 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

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

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with O99.35?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

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.

Code Overview

Diseases of the nervous system complicating pregnancy, childbirth, and the puerperium is a non-billable ICD-10-CM category code (O99.35). A more specific billable subcode must be selected for claims submission.

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Verify Before Coding

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 O99.35 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 10 Excludes2 notes: O20 — Hemorrhage in early pregnancy (via O99.-), O20-O29 — Other maternal disorders predominantly related to pregnancy (O20-O29) (via O99.-), O21 — Excessive vomiting in pregnancy (via O99.-), O22 — Venous complications and hemorrhoids in pregnancy (via O99.-), O23 — Infections of genitourinary tract in pregnancy (via O99.-), O24 — Diabetes mellitus in pregnancy, childbirth, and the puerperium (via O99.-), O25 — Malnutrition in pregnancy, childbirth and the puerperium (via O99.-), O26 — Maternal care for other conditions predominantly related to pregnancy (via O99.-), O28 — Abnormal findings on antenatal screening of mother (via O99.-), O29 — Complications of anesthesia during pregnancy (via O99.-).

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

Contextual Map

Every relationship of O99.35 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 O99.35 with these 9 related codes in Claim Check

Hierarchy

Excludes2

Referenced by Excludes2 notes (10)

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

Common coding questions

Can O99.35 be billed directly?

No. O99.35 (Diseases of the nervous system complicating pregnancy, childbirth, and the puerperium) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

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
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

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Diseases of the nervous system complicating pregnancy, childbirth, and the puerperium

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), 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 O99.35 in its code family, with their registry titles.

View all codes in the O99 family