N91 Absent, scanty and rare menstruation

Category / Non-billable header 6 subcodes

Block: Noninflammatory disorders of female genital tract (N80-N98)

Excludes 1 (cannot be coded together)

  • ovarian dysfunction (E28.-)

Subcodes

Subcodes are listed below for reference. Detail pages are not available for chapters 11–22.

Code Description Billable
N91..0 Primary amenorrhea Yes
N91..1 Secondary amenorrhea Yes
N91..2 Amenorrhea, unspecified Yes
N91..3 Primary oligomenorrhea Yes
N91..4 Secondary oligomenorrhea Yes
N91..5 Oligomenorrhea, unspecified Yes

Last reviewed: September 2026