O91.12 Abscess of breast associated with the puerperium

Billable ICD-10-CM code, FY2026.

Applicable to

• Puerperal mammary abscess
• Puerperal purulent mastitis
• Puerperal subareolar abscess

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

Use additional code

• code to identify infection

MS-DRG index

Defines the logic of DRG(s) 769 in MDC 14.

Approximate ICD-9-CM (GEMs)

• 675.12 Abscess of breast associated with childbirth, delivered, with mention of postpartum complication (approximate)
• 675.14 Abscess of breast associated with childbirth, postpartum condition or complication (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Maternity diagnoses (age 9 through 64): Age conflict edit. These diagnoses are clinically expected only in patients age 9 through 64.

Code annotations containing back-references to O91.12

Back-references to O91

• Type 1 Excludes: N61 Inflammatory disorders of breast ("inflammatory disorder of breast associated with childbirth (O91.-)")

Diagnosis Index entries for O91.12

• Mastitis (acute) (diffuse) (nonpuerperal) (subacute) › obstetric (interstitial) (nonpurulent) › purulent › associated with › puerperium
• Puerperal, puerperium (complicated by, complications) › abscess › breast
• Puerperal, puerperium (complicated by, complications) › abscess › mammary
• Puerperal, puerperium (complicated by, complications) › abscess › subareolar
• Puerperal, puerperium (complicated by, complications) › fistula › breast (due to mastitis)
• Puerperal, puerperium (complicated by, complications) › mastitis › purulent
• Suppuration, suppurative › mammary gland › puerperal, postpartum

Nearby codes

• O91.11 Abscess of breast associated with pregnancy
• O91.111 Abscess of breast associated with pregnancy, first trimester
• O91.112 Abscess of breast associated with pregnancy, second trimester
• O91.113 Abscess of breast associated with pregnancy, third trimester
• O91.119 Abscess of breast associated with pregnancy, unspecified trimester
• O91.12 Abscess of breast associated with the puerperium (this code)
• O91.13 Abscess of breast associated with lactation
• 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 trimester
• O91.212 Nonpurulent mastitis associated with pregnancy, second trimester