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ICD-10 Guide
ICD-10 CodesN91.5

N91.5

Billable

Oligomenorrhea, unspecified

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/18/2025

Code Description

ICD-10 N91.5 is a billable code used to indicate a diagnosis of oligomenorrhea, unspecified.

Key Diagnostic Point:

Oligomenorrhea is defined as infrequent menstrual periods, typically characterized by cycles that occur more than 35 days apart but less than six months. This condition can be a symptom of various underlying health issues, including hormonal imbalances, polycystic ovary syndrome (PCOS), thyroid disorders, and stress-related factors. Women experiencing oligomenorrhea may have fewer than six to eight menstrual cycles per year. The condition can lead to complications such as infertility, as irregular ovulation can hinder conception. Diagnosis often involves a thorough medical history, physical examination, and laboratory tests to assess hormone levels and rule out other conditions. Treatment may vary based on the underlying cause and can include lifestyle modifications, hormonal therapies, or medications aimed at regulating menstrual cycles. Understanding oligomenorrhea is crucial for reproductive health, particularly in the context of female infertility and complications arising from artificial fertilization procedures.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variability in menstrual cycle definitions and patient reporting
  • Need for comprehensive documentation of menstrual history
  • Differentiation from other menstrual disorders like amenorrhea
  • Potential overlap with conditions affecting fertility

Audit Risk Factors

  • Insufficient documentation of menstrual history
  • Failure to specify underlying causes or related conditions
  • Inconsistent coding practices among providers
  • Lack of follow-up documentation for treatment outcomes

Specialty Focus

Medical Specialties

Obstetrics and Gynecology

Documentation Requirements

Detailed menstrual history, physical examination findings, and any relevant lab results.

Common Clinical Scenarios

Patients presenting with irregular menstrual cycles, infertility evaluations, and hormonal therapy management.

Billing Considerations

Ensure clear documentation of the patient's menstrual cycle patterns and any associated symptoms.

Endocrinology

Documentation Requirements

Thorough assessment of hormonal levels, including thyroid and adrenal function tests.

Common Clinical Scenarios

Patients with suspected hormonal imbalances contributing to oligomenorrhea.

Billing Considerations

Document any endocrine disorders that may be influencing menstrual irregularities.

Coding Guidelines

Inclusion Criteria

Use N91.5 When
  • According to ICD
  • 10 guidelines, N91
  • 5 should be used when the specific cause of oligomenorrhea is not documented
  • Coders should ensure that all relevant clinical information is captured to support the diagnosis

Exclusion Criteria

Do NOT use N91.5 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

99213CPT Code

Established patient office visit, Level 3

Clinical Scenario

Used for follow-up visits regarding oligomenorrhea management.

Documentation Requirements

Document the patient's menstrual history and any treatment plans discussed.

Specialty Considerations

Obstetricians should ensure comprehensive documentation of menstrual patterns.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of menstrual disorders, including oligomenorrhea. This specificity aids in better tracking of patient outcomes and treatment efficacy.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of menstrual disorders, including oligomenorrhea. This specificity aids in better tracking of patient outcomes and treatment efficacy.

Reimbursement & Billing Impact

reimbursement.

Resources

Clinical References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Coding & Billing References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Frequently Asked Questions

What is the difference between oligomenorrhea and amenorrhea?

Oligomenorrhea refers to infrequent menstrual periods, while amenorrhea is the absence of menstruation altogether. Proper documentation is essential to differentiate between the two for accurate coding.