2026 ICD-10-CM Diagnosis Code O35.9XX3Maternal care for (suspected) fetal abnormality and damage, unspecified, fetus 3

ICD-10-CM Codes›O00-O9A›O30-O48›O35

ICD-10-CM O35.9XX3
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O35.9XX3 is a billable ICD-10-CM diagnosis code for maternal care for (suspected) fetal abnormality and damage, unspecified, fetus 3. The 7th character 3 identifies fetus 3 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
O35.9XX3
Billable Status
Yes — Valid for Submission
Code Describes
Maternal care for (suspected) fetal abnormality and damage, unspecified, fetus 3
Short Description
Maternal care for fetal abnlt and damage, unsp, fetus 3
Parent Code
O35.9
Maternal care for (suspected) fetal abnormality and damage, unspecified

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 CodeO35.9XX3Maternal care for (suspected) fetal abnormality and damage, unspecified, fetus 3

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O35.9XX3.

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

Birth Defects

A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of pregnancy. One out of every 33 babies in the United States is born with a birth defect.

The full article covers:

  • What are birth defects?
  • What causes birth defects?
  • Who is at risk of having a baby with birth defects?
  • How are birth defects diagnosed?
  • What are the treatments for birth defects?
  • Can birth defects be prevented?

Read the full article at MedlinePlus

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

Convert O35.9XX3 to ICD-9-CMHistory

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

ICD-9-CM
655.91 Fetal abnorm NOS-deliver
Approximate The match is approximate rather than exact.
ICD-9-CM
655.93 Fetal abnorm NOS-antepar
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 O35.9XX3Overview

Is O35.9XX3 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report maternal care for (suspected) fetal abnormality and damage, unspecified, fetus 3 on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character 3 in O35.9XX3 mean?

The final character 3 identifies the fetus in a multiple gestation pregnancy: this code reports maternal care for (suspected) fetal abnormality and damage, unspecified for fetus 3.

What MS-DRG does O35.9XX3 group to?

When maternal care for (suspected) fetal abnormality and damage, unspecified, fetus 3 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 O35.9XX3 be reported for?

The Medicare Code Editor checks maternal care for (suspected) fetal abnormality and damage, unspecified, fetus 3 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 O35.9XX3?

Under the General Equivalence Mappings, maternal care for (suspected) fetal abnormality and damage, unspecified, fetus 3 converts to ICD-9-CM 655.91 (fetal abnorm NOS-deliver) and 655.93 (fetal abnorm NOS-antepar). 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.