2026 ICD-10-CM Diagnosis Code O35.2XX4Maternal care for (suspected) hereditary disease in fetus, fetus 4

ICD-10-CM Codes›O00-O9A›O30-O48›O35

ICD-10-CM O35.2XX4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O35.2XX4 is a billable ICD-10-CM diagnosis code for maternal care for (suspected) hereditary disease in fetus, fetus 4. The 7th character 4 identifies fetus 4 in a multiple gestation pregnancy. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 817 through 819, 831 through 833. The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Maternal care related to fetal conditions.

Code Identity

ICD-10-CM Code
O35.2XX4
Billable Status
Yes — Valid for Submission
Code Describes
Maternal care for (suspected) hereditary disease in fetus, fetus 4
Short Description
Maternal care for hereditary disease in fetus, fetus 4
Parent Code
O35.2
Maternal care for (suspected) hereditary disease in fetus

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO30-O48Maternal care related to the fetus and amniotic cavity and possible delivery problems
CategoryO35Maternal care for known or suspected fetal abnormality and damage
This CodeO35.2XX4Maternal care for (suspected) hereditary disease in fetus, fetus 4

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O35.2XX4.

Maternity diagnoses
The Medicare Code Editor detects inconsistencies in maternity cases by checking a patient's age and any diagnosis on the patient's record. The maternity code edits apply to patients age ange is 9–64 years inclusive (e.g., diabetes in pregnancy, antepartum pulmonary complication).

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR PRG013
Maternal care related to fetal conditions
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Genetic Disorders

Genetic disorders are health conditions caused by changes (also called mutations or variants) in your genes. Genes are parts of DNA found in your cells that carry instructions for how your body grows, develops, and functions. Many genes tell your body how to make proteins, which are needed for your body to work properly.

The full article covers:

  • What are genetic disorders?
  • What causes genetic disorders?
  • What are the types of genetic disorders?
  • What are the different ways a genetic disorder can be inherited?
  • How are genetic disorders diagnosed?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert O35.2XX4 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
655.21 Famil heredit dis-deliv
Approximate The match is approximate rather than exact.
ICD-9-CM
655.23 Famil hered dis-antepart
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About O35.2XX4Overview

Is O35.2XX4 (Maternal care for (suspected) hereditary disease in fetus) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report maternal care for (suspected) hereditary disease in fetus, fetus 4 on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character 4 in O35.2XX4 mean?

The final character 4 identifies the fetus in a multiple gestation pregnancy: this code reports maternal care for (suspected) hereditary disease in fetus for fetus 4.

What MS-DRG does O35.2XX4 group to?

When maternal care for (suspected) hereditary disease in fetus, fetus 4 is the principal diagnosis on an inpatient stay, it groups to MS-DRG 817, 818, 819, 831, 832, 833, with relative weights from 0.5229 to 1.6880 depending on complications. Higher weights mean higher Medicare reimbursement.

Who can O35.2XX4 be reported for?

The Medicare Code Editor checks maternal care for (suspected) hereditary disease in fetus, fetus 4 against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.

What is the ICD-9 equivalent of O35.2XX4?

Under the General Equivalence Mappings, maternal care for (suspected) hereditary disease in fetus, fetus 4 converts to ICD-9-CM 655.21 (famil heredit dis-deliv) and 655.23 (famil hered dis-antepart). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.