2026 ICD-10-CM Diagnosis Code O01.1Incomplete and partial hydatidiform mole

ICD-10-CM Codes›O00-O9A›O00-O08›O01

ICD-10-CM O01.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O01.1 is a billable ICD-10-CM diagnosis code for incomplete and partial hydatidiform mole. 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 gestational trophoblastic disease. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Molar pregnancy and other abnormal products of conception.

Code Identity

ICD-10-CM Code
O01.1
Billable Status
Yes — Valid for Submission
Code Describes
Incomplete and partial hydatidiform mole
Short Description
Incomplete and partial hydatidiform mole
Same as the full description in the CMS dataset.
Parent Code
O01
Hydatidiform mole

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO00-O08Pregnancy with abortive outcome
CategoryO01Hydatidiform mole
This CodeO01.1Incomplete and partial hydatidiform mole

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O01.1.

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.

  • Gestational trophoblastic disease
  • Hydatidiform mole, benign
  • Partial hydatidiform mole

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.

    • Hydatidiform mole(benign) (complicating pregnancy) (delivered) (undelivered)
      • incomplete
    • Hydatidiform mole(benign) (complicating pregnancy) (delivered) (undelivered)
      • partial
    • Mole(pigmented)
      • hydatid, hydatidiform (benign) (complicating pregnancy) (delivered) (undelivered)
        • incomplete
    • Mole(pigmented)
      • hydatid, hydatidiform (benign) (complicating pregnancy) (delivered) (undelivered)
        • partial

Clinical ClassificationClinical

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

CCSR PRG006
Molar pregnancy and other abnormal products of conception
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Gestational Trophoblastic Disease

    a group of diseases arising from pregnancy that are commonly associated with hyperplasia of trophoblasts (trophoblast) and markedly elevated human chorionic gonadotropin. they include hydatidiform mole, invasive mole (hydatidiform mole, invasive), placental-site trophoblastic tumor (trophoblastic tumor, placental site), and choriocarcinoma. these neoplasms have varying propensities for invasion and spread.

Patient EducationClinical

Tumors and Pregnancy

Tumors during pregnancy are rare, but they can happen. Tumors can be either benign (not cancer) or malignant (cancer). The most common cancers in pregnancy include breast cancer, thyroid cancer, cervical cancer, lymphoma, and melanoma. Cancer itself rarely harms the fetus, and some cancer treatments are safe during pregnancy.

Read the full article at MedlinePlus

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

Convert O01.1 to ICD-9-CMHistory

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

ICD-9-CM
630 Hydatidiform mole
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 O01.1Overview

Is O01.1 (Hydatidiform mole) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report incomplete and partial hydatidiform mole on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does O01.1 group to?

When incomplete and partial hydatidiform mole 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 O01.1 be reported for?

The Medicare Code Editor checks incomplete and partial hydatidiform mole 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 O01.1?

Under the General Equivalence Mappings, incomplete and partial hydatidiform mole converts to ICD-9-CM 630 (hydatidiform mole). 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.