ICD-10-CM 2027
ICD-10 code for oligomenorrhea
From the official ICD-10-CM alphabetic index entry “Oligomenorrhea”. Page updated September 29, 2026.
About coding oligomenorrhea
The ICD-10-CM code for oligomenorrhea is N91.5 (Oligomenorrhea, unspecified). The official index lists 2 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on N91.5.
Within N91, choose N91.5 (Oligomenorrhea, unspecified) only when documentation doesn't support a more specific option: primary amenorrhea (N91.0), secondary amenorrhea (N91.1), amenorrhea, unspecified (N91.2), primary oligomenorrhea (N91.3) and secondary oligomenorrhea (N91.4).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 742 (Uterine and Adnexa Procedures for Non-Malignancy with CC/MCC, relative weight 1.8456), DRG 743 (Uterine and Adnexa Procedures for Non-Malignancy without CC/MCC, relative weight 1.2974), DRG 760 (Menstrual and Other Female Reproductive System Disorders with CC/MCC, relative weight 1.0129) and DRG 761 (Menstrual and Other Female Reproductive System Disorders without CC/MCC, relative weight 0.7041), in MDC 13 (Diseases and Disorders of the Female Reproductive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific oligomenorrhea codes (official index)
Common questions about oligomenorrhea ICD-10 codes
What is the ICD-10 code for oligomenorrhea?
- N91.5 — Oligomenorrhea, unspecified. More specific codes apply when the documentation supports them: N91.3, N91.4.
What is the ICD-10 code for primary oligomenorrhea?
- N91.3 — Primary oligomenorrhea.
What is the ICD-10 code for secondary oligomenorrhea?
- N91.4 — Secondary oligomenorrhea.
Is N91.5 billable?
- Yes. N91.5 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can N91.5 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict N91.5 as a principal diagnosis.
Is N91.5 a CC or MCC?
- No. N91.5 is neither a CC nor an MCC under MS-DRG v44.0.