DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Category · FY2027

O91 Infections of breast associated with pregnancy, the puerperium and lactation

  • Header · not billable

O91 is not billable. The category heads 18 billable codes in FY2027, grouped under 3 subdivisions.

Index → code

  • Gestationalmammary abscess → O91.11-
  • Gestationalpurulent mastitis → O91.11-
  • Gestationalsubareolar abscess → O91.11-

Where it sits

  1. Chapter 15 Pregnancy, childbirth and the puerperium (O00-O9A)
  2. O85-O92 Complications predominantly related to the puerperium (O85-O92)
  3. O91 Infections of breast associated with pregnancy, the puerperium and lactation
Billable codes
18
Subdivisions
3
CC / MCC codes
0 / 0
HCC V28 codes
0
New FY2027
0
Index entries
51

Codes in O91

  1. O91.0
    Infection of nipple associated with pregnancy, the puerperium and lactation
    Header
  2. O91.01
    Infection of nipple associated with pregnancy
    Header
    Inclusion terms 1

    Inclusion terms

    • Gestational abscess of nipple
  3. O91.011
    Infection of nipple associated with pregnancy, first trimester
    Billable
  4. O91.012
    Infection of nipple associated with pregnancy, second trimester
    Billable
  5. O91.013
    Infection of nipple associated with pregnancy, third trimester
    Billable
  6. O91.019
    Infection of nipple associated with pregnancy, unspecified trimester
    Billable
  7. O91.02
    Infection of nipple associated with the puerperium
    Billable
    Inclusion terms 1

    Inclusion terms

    • Puerperal abscess of nipple
  8. O91.03
    Infection of nipple associated with lactation
    Billable
    Inclusion terms 1

    Inclusion terms

    • Abscess of nipple associated with lactation
  9. O91.1
    Abscess of breast associated with pregnancy, the puerperium and lactation
    Header
  10. O91.11
    Abscess of breast associated with pregnancy
    Header
    Inclusion terms 3

    Inclusion terms

    • Gestational mammary abscess
    • Gestational purulent mastitis
    • Gestational subareolar abscess
  11. O91.111
    Abscess of breast associated with pregnancy, first trimester
    Billable
  12. O91.112
    Abscess of breast associated with pregnancy, second trimester
    Billable
  13. O91.113
    Abscess of breast associated with pregnancy, third trimester
    Billable
  14. O91.119
    Abscess of breast associated with pregnancy, unspecified trimester
    Billable
  15. O91.12
    Abscess of breast associated with the puerperium
    Billable
    Inclusion terms 3

    Inclusion terms

    • Puerperal mammary abscess
    • Puerperal purulent mastitis
    • Puerperal subareolar abscess
  16. O91.13
    Abscess of breast associated with lactation
    Billable
    Inclusion terms 3

    Inclusion terms

    • Mammary abscess associated with lactation
    • Purulent mastitis associated with lactation
    • Subareolar abscess associated with lactation
  17. O91.2
    Nonpurulent mastitis associated with pregnancy, the puerperium and lactation
    Header
  18. O91.21
    Nonpurulent mastitis associated with pregnancy
    Header
    Inclusion terms 4

    Inclusion terms

    • Gestational interstitial mastitis
    • Gestational lymphangitis of breast
    • Gestational mastitis NOS
    • Gestational parenchymatous mastitis
  19. O91.211
    Nonpurulent mastitis associated with pregnancy, first trimester
    Billable
  20. O91.212
    Nonpurulent mastitis associated with pregnancy, second trimester
    Billable
  21. O91.213
    Nonpurulent mastitis associated with pregnancy, third trimester
    Billable
  22. O91.219
    Nonpurulent mastitis associated with pregnancy, unspecified trimester
    Billable
  23. O91.22
    Nonpurulent mastitis associated with the puerperium
    Billable
    Inclusion terms 4

    Inclusion terms

    • Puerperal interstitial mastitis
    • Puerperal lymphangitis of breast
    • Puerperal mastitis NOS
    • Puerperal parenchymatous mastitis
  24. O91.23
    Nonpurulent mastitis associated with lactation
    Billable
    Inclusion terms 4

    Inclusion terms

    • Interstitial mastitis associated with lactation
    • Lymphangitis of breast associated with lactation
    • Mastitis NOS associated with lactation
    • Parenchymatous mastitis associated with lactation

Sources of each column.

Instructions

At O91

Use additional code

  • code to identify infection

Notes that also apply

Block O85-O92 instructions (Excludes2 3): printed on the block page.

Chapter 15 instructions (Notes 6, Excludes1 1, Excludes2 4, Use additional code 1): printed on the chapter 15 page.

Index entries

  • Mammillitispuerperal, postpartum → O91.02
  • Puerperal, puerperium (complicated by, complications)mammillitis → O91.02
  • Puerperal, puerperium (complicated by, complications)thelitis → O91.02
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)gestational mammary → O91.11-
  • Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)gestational subareolar → O91.11-
  • Gestationalmammary abscess → O91.11-
  • Gestationalpurulent mastitis → O91.11-
  • Gestationalsubareolar abscess → O91.11-
  • Galactophoritisgestational, puerperal, postpartum → O91.2-
  • Puerperal, puerperium (complicated by, complications)galactophoritis → O91.22
  • Puerperal, puerperium (complicated by, complications)mammitis → O91.22
  • Puerperal, puerperium (complicated by, complications)mastitis → O91.22
  • Puerperal, puerperium (complicated by, complications)abscessareola → O91.02
  • Puerperal, puerperium (complicated by, complications)abscessnipple → O91.02
  • Puerperal, puerperium (complicated by, complications)fistulanipple → O91.02
  • Puerperal, puerperium (complicated by, complications)infectionnipple → O91.02
  • Puerperal, puerperium (complicated by, complications)mammillitisassociated with lactation → O91.03
  • Puerperal, puerperium (complicated by, complications)thelitisassociated with lactation → O91.03
  • Puerperal, puerperium (complicated by, complications)abscessbreast → O91.12
  • Puerperal, puerperium (complicated by, complications)abscessmammary → O91.12
  • Puerperal, puerperium (complicated by, complications)abscesssubareolar → O91.12
  • Puerperal, puerperium (complicated by, complications)fistulabreast (due to mastitis) → O91.12
  • Puerperal, puerperium (complicated by, complications)mastitispurulent → O91.12
  • Suppuration, suppurativemammary glandpuerperal, postpartum → O91.12
  • Lymphadenitisbreastpuerperal, postpartum (nonpurulent) → O91.22
  • Puerperal, puerperium (complicated by, complications)lymphangitisbreast → O91.22
  • Puerperal, puerperium (complicated by, complications)galactophoritisassociated with lactation → O91.23
  • Puerperal, puerperium (complicated by, complications)mammitisassociated with lactation → O91.23
  • Puerperal, puerperium (complicated by, complications)mastitisassociated with lactation → O91.23
  • Infection, infected, infective (opportunistic)nippleassociated withpregnancy → O91.01-
  • Pregnancy (single) (uterine)complicated by (care of) (management affected by)infection(s)nipple → O91.01-
  • Infection, infected, infective (opportunistic)nippleassociated withpuerperium → O91.02
  • Infection, infected, infective (opportunistic)nippleassociated withlactation → O91.03
  • Puerperal, puerperium (complicated by, complications)abscessareolaassociated with lactation → O91.03
  • Puerperal, puerperium (complicated by, complications)abscessnippleassociated with lactation → O91.03
  • Puerperal, puerperium (complicated by, complications)fistulanippleassociated with lactation → O91.03
  • Puerperal, puerperium (complicated by, complications)infectionnippleassociated with lactation → O91.03
  • Pregnancy (single) (uterine)complicated by (care of) (management affected by)abscess or cellulitisbreast → O91.11-
  • Puerperal, puerperium (complicated by, complications)abscessbreastassociated with lactation → O91.13
  • Puerperal, puerperium (complicated by, complications)abscessmammaryassociated with lactation → O91.13

11 more, longer entries are not listed; the search box finds them by word.

NCHS Alphabetic Index. Index first, then the Tabular List.

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