2026 ICD-10-CM Diagnosis Code O02.81Inappropriate change in quantitative human chorionic gonadotropin (hCG) in early pregnancy

ICD-10-CM Codes›O00-O9A›O00-O08›O02

ICD-10-CM O02.81
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O02.81 is a billable ICD-10-CM diagnosis code for inappropriate change in quantitative human chorionic gonadotropin (hCG) in early 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). Coders also document this condition as abnormal hormone secretion. 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
O02.81
Billable Status
Yes — Valid for Submission
Code Describes
Inappropriate change in quantitative human chorionic gonadotropin (hCG) in early pregnancy
Short Description
Inapprop chg quantitav hCG in early pregnancy
Parent Code
O02.8
Other specified abnormal products of conception

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO00-O08Pregnancy with abortive outcome
CategoryO02Other abnormal products of conception
This CodeO02.81Inappropriate change in quantitative human chorionic gonadotropin (hCG) in early pregnancy

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O02.81.

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.

  • Abnormal hormone secretion
  • Abnormal placental secretion of chorionic gonadotropin
  • Absence of placental secretion of chorionic gonadotropin
  • Biochemical pregnancy
  • Finding related to placental secretion of chorionic gonadotropin

Tabular List NotesGuidance

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

Inclusion Terms

  • Biochemical pregnancy
  • Chemical pregnancy
  • Inappropriate level of quantitative human chorionic gonadotropin (hCG) for gestational age in early pregnancy

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.

    • Inappropriate
      • change in quantitative human chorionic gonadotropin (hCG) in early pregnancy
    • Inappropriate
      • level of quantitative human chorionic gonadotropin (hCG) for gestational age in early pregnancy
    • Pregnancy(single) (uterine)
      • biochemical
    • Pregnancy(single) (uterine)
      • chemical

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

Convert O02.81 to ICD-9-CMHistory

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

ICD-9-CM
631.0 Inapp chg hCG early preg
Exact Match The mapping is direct, with no qualifiers.

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 O02.81Overview

Is O02.81 (Other specified abnormal products of conception) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report inappropriate change in quantitative human chorionic gonadotropin (hCG) in early pregnancy on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does O02.81 group to?

When inappropriate change in quantitative human chorionic gonadotropin (hCG) in early pregnancy 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 O02.81 be reported for?

The Medicare Code Editor checks inappropriate change in quantitative human chorionic gonadotropin (hCG) in early pregnancy 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 O02.81?

Under the General Equivalence Mappings, inappropriate change in quantitative human chorionic gonadotropin (hCG) in early pregnancy converts to ICD-9-CM 631.0 (inapp chg hCG early preg). The mapping is a direct match.

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.