2026 ICD-10-CM Diagnosis Code O91Infections of breast associated with pregnancy, the puerperium and lactation

ICD-10-CM Codes›O00-O9A›O85-O92›O91

ICD-10-CM O91
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O91 is a non-billable ICD-10-CM category code for infections of breast associated with pregnancy, the puerperium and lactation, so it cannot be submitted on claims. Use a more specific code from this category instead, such as O91.011, O91.012, O91.013, and O91.019.

Code Identity

ICD-10-CM Code
O91
Billable Status
No — Non-Billable Category
Code Describes
Infections of breast associated with pregnancy, the puerperium and lactation
Chapter
O85-O92
Complications predominantly related to the puerperium

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO85-O92Complications predominantly related to the puerperium
CategoryO91Infections of breast associated with pregnancy, the puerperium and lactation
This CodeO91Infections of breast associated with pregnancy, the puerperium and lactation

Specific Coding for Infect of breast assoc w pregnancy, the puerp and lactationOverview

Non-specific codes like O91 require more characters. Use one of these billable codes instead:

  • O91.0 for Infection of nipple associated with pregnancy, the puerperium and lactation

  • O91.01 for Infection of nipple associated with pregnancy

  • Use O91.02 for Infection of nipple associated with the puerperium

  • Use O91.03 for Infection of nipple associated with lactation

  • O91.1 for Abscess of breast associated with pregnancy, the puerperium and lactation

  • O91.11 for Abscess of breast associated with pregnancy

  • Use O91.12 for Abscess of breast associated with the puerperium

  • Use O91.13 for Abscess of breast associated with lactation

  • O91.2 for Nonpurulent mastitis associated with pregnancy, the puerperium and lactation

  • O91.21 for Nonpurulent mastitis associated with pregnancy

  • Use O91.22 for Nonpurulent mastitis associated with the puerperium

  • Use O91.23 for Nonpurulent mastitis associated with lactation

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Use Additional Code

  • code to identify infection

Patient EducationClinical

Breast Diseases

Breast diseases include various conditions and changes in your breast. Most women experience breast changes at some time. Your age, hormone levels, and medicines you take may cause lumps, bumps, and discharges of fluids that are not breast milk.

The full article covers:

  • What are breast diseases?
  • What are the symptoms of breast disease?
  • How are breast diseases diagnosed?
  • What are the treatments for breast disease?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About O91Overview

Is O91 a billable code?

No. This is a category header that groups the codes for infections of breast associated with pregnancy, the puerperium and lactation, and headers cannot be submitted on claims. Claims for infections of breast associated with pregnancy, the puerperium and lactation need a more specific code from this category, such as O91.011, O91.012, and O91.013.