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Ob-Gyn Coding Alert


Diagnosis Specifies Whether Amenorrhea Is Primary or Secondary

Plus, don’t miss this news about Excludes1 notes.

Amenorrhea refers to the absence of menses for three months or more. It can primary or secondary in nature.

You should report this condition with the following codes:

  • N91.0, Primary amenorrhea
  • N91.1, Secondary amenorrhea
  • N91.2, Amenorrhea, unspecified

Prior to ICD-10’s implementation, you only had one diagnosis code to describe “absence of menstruation.”

Documentation: A provider will document “primary amenorrhea” when a girl has not started her periods. She may have gone through other normal changes that occur during puberty, and she is older than 15. “Secondary amenorrhea” means the patient has not gotten her period for over 3-6 months. You should not consider a woman who is pregnant, breastfeeding, or in menopause as having secondary amenorrhea.

Here is how you will find these codes in your Alphabetic Index:

Amenorrhea N91.2
- primary N91.0
- secondary N91.1

Delay, delayed

- menstruation (cause unknown) N91.0


- absent —see Amenorrhea
- delayed N91.0

Coder Tips: Underneath the N91- category (Absent, scanty and rare menstruation), you will see an Excludes1 note that states you should not report these codes with ovarian dysfunction (E28).  

Have you heard the news? Reporting a code together with codes from its Excludes1 list may be appropriate when the conditions are unrelated.

Although the ICD-10-CM Tabular List states that an “Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note,” that rule caused issues for certain code combinations.

To resolve those issues, an interim rule is in place: “If the two conditions are not related to one another, it is permissible to report both codes despite the presence of an Excludes1 note,” according to advice approved by AHIMA, AHA, CMS, and NCHS (

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