2027 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 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

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 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 998. 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

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to O66.41: its own notes plus those printed at Chapter 15. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • supervision of normal pregnancy (Z34.-)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • mental and behavioral disorders associated with the puerperium (F53.-)
  • obstetrical tetanus (A34)
  • postpartum necrosis of pituitary gland (E23.0)
  • puerperal osteomalacia (M83.0)

Code First

The underlying condition named in the note is sequenced before this code.

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.

Notes

General instructions on how these codes are used.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • CODES FROM THIS CHAPTER ARE FOR USE ONLY ON MATERNAL RECORDS, NEVER ON NEWBORN RECORDS
  • Codes from this chapter are for use for conditions related to or aggravated by the pregnancy, childbirth, or by the puerperium (maternal causes or obstetric causes)
  • Trimesters are counted from the first day of the last menstrual period. They are defined as follows:
  • 1st trimester- less than 14 weeks 0 days
  • 2nd trimester- 14 weeks 0 days to less than 28 weeks 0 days
  • 3rd trimester- 28 weeks 0 days until delivery

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name O66.41, its category, or a range that includes it.

Applicable To 1

These notes mention O66.41.

  • P03.1 Newborn affected by other malpresentation, malposition and disproportion during labor and delivery
    Newborn affected by conditions classifiable to O64-O66 names O64-O66, which includes this code

Excludes1 1

These codes carry an Excludes1 note naming O66.41: they are not reported together with it, unless the two conditions are unrelated.

  • O33 Maternal care for disproportion
    disproportion with obstructed labor (O65-O66) names O65-O66, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About O66.41Overview

What is the ICD-10 code for failed attempted vaginal birth after previous cesarean delivery?

The ICD-10-CM code for failed attempted vaginal birth after previous cesarean delivery is O66.41 (sometimes written as O6641). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

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, 2026 through September 30, 2027.

What MS-DRG does O66.41 group to?

When failed attempted vaginal birth after previous cesarean delivery is the principal diagnosis on an inpatient stay, it groups to MS-DRG 998 (principal Diagnosis Invalid as Discharge Diagnosis), which carries a relative weight of 0. Higher weights mean higher Medicare reimbursement.

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 coded first with O66.41?

The Code First note reads: rupture of uterus, if applicable (O71.0-, O71.1). When one of these applies, it is sequenced before O66.41.