N91.0 Primary amenorrhea

Billable ICD-10-CM code, FY2026.

Applies from N91 Absent, scanty and rare menstruation

Excludes1 (never code together)

• ovarian dysfunction (E28.-)

MS-DRG index

Defines the logic of DRG(s) 742-743 in MDC 13.

Approximate ICD-9-CM (GEMs)

• 626.0 Absence of menstruation (approximate)

Diagnosis Index entries for N91.0

• Amenorrhea › primary
• Delay, delayed › menstruation (cause unknown)
• Failure, failed › menstruation at puberty
• Menstruation › delayed

Nearby codes

• N91 Absent, scanty and rare menstruation
• N91.0 Primary amenorrhea (this code)
• N91.1 Secondary amenorrhea
• N91.2 Amenorrhea, unspecified
• N91.3 Primary oligomenorrhea
• N91.4 Secondary oligomenorrhea
• N91.5 Oligomenorrhea, unspecified