2026 ICD-10-CM Diagnosis Code O66.3Obstructed labor due to other abnormalities of fetus

ICD-10-CM Codes›O00-O9A›O60-O77›O66

ICD-10-CM O66.3
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O66.3 is a billable ICD-10-CM diagnosis code for obstructed labor due to other abnormalities of fetus. 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). Coders also document this condition as obstructed labor due to fetal abnormality. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Malposition, disproportion or other labor complications.

Code Identity

ICD-10-CM Code
O66.3
Billable Status
Yes — Valid for Submission
Code Describes
Obstructed labor due to other abnormalities of fetus
Short Description
Obstructed labor due to other abnormalities of fetus
Same as the full description in the CMS dataset.
Parent Code
O66
Other obstructed labor

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO60-O77Complications of labor and delivery
CategoryO66Other obstructed labor
This CodeO66.3Obstructed labor due to other abnormalities of fetus

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O66.3.

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.

  • Obstructed labor due to fetal abnormality

Tabular List NotesGuidance

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

Inclusion Terms

  • Dystocia due to fetal ascites
  • Dystocia due to fetal hydrops
  • Dystocia due to fetal meningomyelocele
  • Dystocia due to fetal sacral teratoma
  • Dystocia due to fetal tumor
  • Dystocia due to hydrocephalic fetus

Use Additional Code

  • code to identify cause of obstruction

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.

    • Deformity
      • fetal
        • causing obstructed labor
    • Delivery(childbirth) (labor)
      • complicated
        • by
          • fetal
            • deformity
    • Delivery(childbirth) (labor)
      • complicated
        • by
          • obstructed labor
            • due to
              • dystocia (fetal)
                • due to
                  • conjoined twins
    • Delivery(childbirth) (labor)
      • complicated
        • by
          • obstructed labor
            • due to
              • dystocia (fetal)
                • due to
                  • fetal
                    • abnormality NEC
    • Delivery(childbirth) (labor)
      • complicated
        • by
          • obstructed labor
            • due to
              • dystocia (fetal)
                • due to
                  • fetal
                    • ascites
    • Delivery(childbirth) (labor)
      • complicated
        • by
          • obstructed labor
            • due to
              • dystocia (fetal)
                • due to
                  • fetal
                    • hydrops
    • Delivery(childbirth) (labor)
      • complicated
        • by
          • obstructed labor
            • due to
              • dystocia (fetal)
                • due to
                  • fetal
                    • meningomyelocele
    • Delivery(childbirth) (labor)
      • complicated
        • by
          • obstructed labor
            • due to
              • dystocia (fetal)
                • due to
                  • fetal
                    • sacral teratoma
    • Delivery(childbirth) (labor)
      • complicated
        • by
          • obstructed labor
            • due to
              • dystocia (fetal)
                • due to
                  • fetal
                    • tumor
    • Delivery(childbirth) (labor)
      • complicated
        • by
          • obstructed labor
            • due to
              • dystocia (fetal)
                • due to
                  • hydrocephalic fetus
    • Dystocia
      • fetal
        • abnormality NEC
    • Dystocia
      • fetal
        • conjoined twins
    • Hydrocephalus(acquired) (external) (internal) (malignant) (recurrent)
      • causing disproportion
        • with obstructed labor
    • Hydrops
      • causing obstructed labor (mother)

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

Clinical InformationClinical

  • Obstructed Labor

    a physical barrier to the natural delivery of a baby.

Patient EducationClinical

Childbirth Problems

Childbirth is the process of giving birth to a baby. It includes labor and delivery. Usually everything goes well, but problems can happen. They may cause a risk to the mother, baby, or both. Some of the more common childbirth problems include:

Read the full article at MedlinePlus

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

Convert O66.3 to ICD-9-CMHistory

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

ICD-9-CM
660.81 Obstruct labor NEC-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 O66.3Overview

Is O66.3 (Other obstructed labor) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report obstructed labor due to other abnormalities of fetus on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does O66.3 group to?

When obstructed labor due to other abnormalities of fetus 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 O66.3 be reported for?

The Medicare Code Editor checks obstructed labor due to other abnormalities of fetus 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 O66.3?

Under the General Equivalence Mappings, obstructed labor due to other abnormalities of fetus converts to ICD-9-CM 660.81 (obstruct labor NEC-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.