ICD-10 · PDGM grouping
O91 Infections of breast associated with pregnancy, the puerperium and lactation
All 18 codes in the O91 family, with the PDGM clinical group, comorbidity subgroup and primary-position rule CMS assigns, read from the CMS grouper crosswalk v07.2.26 and the CDC FY2027 code file.
Codes in family
18
Can lead a claim
16
Cannot lead a claim
2
What CMS assigns to O91
16 of the 18 codes group to MMTA - Other (11) and Wound (5); 2 are assigned no clinical group. None of the 18 is assigned a comorbidity subgroup. 16 of the 18 can lead a claim.
Every code in O91
Descriptions are CDC’s FY2027 wording; where CMS’s grouper abbreviates one, its form is shown beneath.
| Code | Description | Primary position | Clinical group | Comorbidity subgroup |
|---|---|---|---|---|
| O91.0 Infection of nipple associated with pregnancy, the puerperium and lactation | ||||
| O91.01 Infection of nipple associated with pregnancy | ||||
| O91.011 | Infection of nipple associated with pregnancy, first trimesterCMS: Infection of nipple associated w pregnancy, first trimester | Can lead a claim | A | None |
| O91.012 | Infection of nipple associated with pregnancy, second trimesterCMS: Infection of nipple associated w pregnancy, second trimester | Can lead a claim | A | None |
| O91.013 | Infection of nipple associated with pregnancy, third trimesterCMS: Infection of nipple associated w pregnancy, third trimester | Can lead a claim | A | None |
| O91.019 | Infection of nipple associated with pregnancy, unspecified trimesterCMS: Infection of nipple associated w pregnancy, unsp trimester | Can lead a claim | A | None |
| O91.02 | Infection of nipple associated with the puerperium | Can lead a claim | A | None |
| O91.03 | Infection of nipple associated with lactation | Can lead a claim | A | None |
| O91.1 Abscess of breast associated with pregnancy, the puerperium and lactation | ||||
| O91.11 Abscess of breast associated with pregnancy | ||||
| O91.111 | Abscess of breast associated with pregnancy, first trimester | Can lead a claim | C | None |
| O91.112 | Abscess of breast associated with pregnancy, second trimesterCMS: Abscess of breast associated w pregnancy, second trimester | Can lead a claim | C | None |
| O91.113 | Abscess of breast associated with pregnancy, third trimester | Can lead a claim | C | None |
| O91.119 | Abscess of breast associated with pregnancy, unspecified trimesterCMS: Abscess of breast associated with pregnancy, unsp trimester | Cannot lead a claimPrincipal diagnosis not assigned to a clinical group | None | None |
| O91.12 | Abscess of breast associated with the puerperium | Can lead a claim | C | None |
| O91.13 | Abscess of breast associated with lactation | Can lead a claim | C | None |
| O91.2 Nonpurulent mastitis associated with pregnancy, the puerperium and lactation | ||||
| O91.21 Nonpurulent mastitis associated with pregnancy | ||||
| O91.211 | Nonpurulent mastitis associated with pregnancy, first trimesterCMS: Nonpurulent mastitis associated w pregnancy, first trimester | Can lead a claim | A | None |
| O91.212 | Nonpurulent mastitis associated with pregnancy, second trimesterCMS: Nonpurulent mastitis assoc w pregnancy, second trimester | Can lead a claim | A | None |
| O91.213 | Nonpurulent mastitis associated with pregnancy, third trimesterCMS: Nonpurulent mastitis associated w pregnancy, third trimester | Can lead a claim | A | None |
| O91.219 | Nonpurulent mastitis associated with pregnancy, unspecified trimesterCMS: Nonpurulent mastitis associated w pregnancy, unsp trimester | Cannot lead a claimPrincipal diagnosis not assigned to a clinical group | None | None |
| O91.22 | Nonpurulent mastitis associated with the puerperium | Can lead a claim | A | None |
| O91.23 | Nonpurulent mastitis associated with lactation | Can lead a claim | A | None |
Sources: CMS HH PPS Grouper Software v07.2.26, effective 2026-10-01, for the clinical group, comorbidity subgroup, code-first conventions and primary-position flags; CDC NCHS ICD-10-CM FY2027 code descriptions for the family title and code wording. This is the crosswalk Medicare runs a claim through. Grouping also depends on admission source, timing, the OASIS functional items and the rest of the diagnosis list.
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