2026 ICD-10-CM Diagnosis Code O66.41Failed attempted vaginal birth after previous cesarean delivery

ICD-10-CM Codes›O00-O9A›O60-O77›O66

ICD-10-CM O66.41
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O66.41 is a billable ICD-10-CM diagnosis code for failed attempted vaginal birth after previous cesarean delivery. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64). Coders also document this condition as failed attempted vaginal birth after previous cesarean section. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Malposition, disproportion or other labor complications.

Code Identity

ICD-10-CM Code
O66.41
Billable Status
Yes — Valid for Submission
Code Describes
Failed attempted vaginal birth after previous cesarean delivery
Short Description
Failed attempt vaginal birth after previous cesarean del
Parent Code
O66.4
Failed trial of labor

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO60-O77Complications of labor and delivery
CategoryO66Other obstructed labor
This CodeO66.41Failed attempted vaginal birth after previous cesarean delivery

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O66.41.

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).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Failed attempted vaginal birth after previous cesarean section

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Code First

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Delivery(childbirth) (labor)
      • cesarean (for)
        • failed
          • trial of labor NOS
            • following previous cesarean delivery
    • Delivery(childbirth) (labor)
      • complicated
        • by
          • failed
            • attempted vaginal birth after previous cesarean delivery
    • Failure, failed
      • trial of labor (with subsequent cesarean delivery)
        • following previous cesarean delivery

Clinical ClassificationClinical

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

CCSR PRG024
Malposition, disproportion or other labor complications
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Cesarean Delivery

A cesarean delivery, also called a cesarean section or c-section, is surgery to deliver a baby. The baby is taken out through your abdomen (belly). In the United States, almost one in three babies are born this way. Some cesarean deliveries are planned.

The full article covers:

  • What is a cesarean delivery?
  • When is a cesarean delivery needed?
  • How is a cesarean delivery done?
  • What are the risks of a cesarean delivery?

Read the full article at MedlinePlus

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

Convert O66.41 to ICD-9-CMHistory

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

ICD-9-CM
660.61 Fail trial lab NOS-deliv
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 O66.41Overview

Is O66.41 (Failed trial of labor) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report failed attempted vaginal birth after previous cesarean delivery on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Who can O66.41 be reported for?

The Medicare Code Editor checks failed attempted vaginal birth after previous cesarean delivery 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 O66.41?

Under the General Equivalence Mappings, failed attempted vaginal birth after previous cesarean delivery converts to ICD-9-CM 660.61 (fail trial lab NOS-deliv). 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.