2026 ICD-10-CM Diagnosis Code N98.1Hyperstimulation of ovaries

ICD-10-CM Codes›N00–N99›N80-N98›N98

ICD-10-CM N98.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

N98.1 is a billable ICD-10-CM diagnosis code for hyperstimulation of ovaries. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 919 through 921. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Postprocedural or postoperative genitourinary system complication.

Code Identity

ICD-10-CM Code
N98.1
Billable Status
Yes — Valid for Submission
Code Describes
Hyperstimulation of ovaries
Short Description
Hyperstimulation of ovaries
Same as the full description in the CMS dataset.
Parent Code
N98
Complications associated with artificial fertilization

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN80-N98Noninflammatory disorders of female genital tract
CategoryN98Complications associated with artificial fertilization
This CodeN98.1Hyperstimulation of ovaries

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Hyperstimulation of ovaries
  • Mild to moderate hyperstimulation of ovaries
  • Ovarian hyperstimulation syndrome
  • Severe hyperstimulation of ovaries

Tabular List NotesGuidance

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

Inclusion Terms

  • Hyperstimulation of ovaries NOS
  • Hyperstimulation of ovaries associated with induced ovulation

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.

    • Complication(s) (from) (of)
      • artificial
        • fertilization or insemination
          • hyperstimulation of ovaries
    • Hyperstimulation, ovaries(associated with induced ovulation)

Clinical ClassificationClinical

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

CCSR GEN026
Postprocedural or postoperative genitourinary system complication
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Ovarian Hyperstimulation Syndrome

    a complication of ovulation induction in infertility treatment. it is graded by the severity of symptoms which include ovary enlargement, multiple ovarian follicles; ovarian cysts; ascites; and generalized edema. the full-blown syndrome may lead to renal failure, respiratory distress, and even death. increased capillary permeability is caused by the vasoactive substances, such as vascular endothelial growth factors, secreted by the overly-stimulated ovaries.

Patient EducationClinical

Assisted Reproductive Technology

Assisted reproductive technology (ART) is used to treat infertility. It includes fertility treatments that handle both eggs and sperm. It works by removing eggs from the ovaries. The eggs are then mixed with sperm to make embryos. The embryos are then put back in the parent's body.

Read the full article at MedlinePlus

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

Convert N98.1 to ICD-9-CMHistory

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

ICD-9-CM
256.1 Ovarian hyperfunc NEC
Approximate The match is approximate rather than exact.
ICD-9-CM
997.99 Surg compl-body syst NEC
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 N98.1Overview

Is N98.1 (Complications associated with artificial fertilization) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report hyperstimulation of ovaries on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does N98.1 group to?

When hyperstimulation of ovaries is the principal diagnosis on an inpatient stay, it groups to MS-DRG 919, 920, 921, with relative weights from 0.6884 to 1.8308 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of N98.1?

Under the General Equivalence Mappings, hyperstimulation of ovaries converts to ICD-9-CM 256.1 (ovarian hyperfunc NEC) and 997.99 (surg compl-body syst NEC). 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.