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

N98.1 is a billable ICD-10-CM diagnosis code for hyperstimulation of ovaries. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 919 through 921. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 48 closely related codes. 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

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to N98.1: its own notes plus those printed at Chapter 14. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

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

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 14 (N00-N99) Diseases of the genitourinary system applies to 838 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

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

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name N98.1, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming N98.1: its condition is not part of those codes, and both may be reported when the patient has both.

  • Z31 Encounter for procreative management
    complications associated with artificial fertilization (N98.-) names N98.-, 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 GEN026
Postprocedural or postoperative genitourinary system complication
Default principal diagnosis: inpatient Yes · outpatient Yes

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

Questions About N98.1Overview

What is the ICD-10 code for hyperstimulation of ovaries?

The ICD-10-CM code for hyperstimulation of ovaries is N98.1 (sometimes written as N981). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

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, 2026 through September 30, 2027.

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 920, 919, 921, with relative weights from 0.6719 to 1.7624 depending on complications. Higher weights mean higher Medicare reimbursement.

Is N98.1 a CC or MCC?

CMS lists N98.1 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 48 closely related codes in its exclusion list.

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.