2026 ICD-10-CM Diagnosis Code P39.0Neonatal infective mastitis

ICD-10-CM Codes›P00–P96›P35-P39›P39

ICD-10-CM P39.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

P39.0 is a billable ICD-10-CM diagnosis code for neonatal infective mastitis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Perinatal infections.

Code Identity

ICD-10-CM Code
P39.0
Billable Status
Yes — Valid for Submission
Code Describes
Neonatal infective mastitis
Short Description
Neonatal infective mastitis
Same as the full description in the CMS dataset.
Parent Code
P39
Other infections specific to the perinatal period

Code Classification

ChapterP00–P96Certain conditions originating in the perinatal period
SectionP35-P39Infections specific to the perinatal period
CategoryP39Other infections specific to the perinatal period
This CodeP39.0Neonatal infective mastitis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abscess of breast
  • Abscess of chest wall
  • Abscess of nipple
  • Abscess of skin of breast
  • Actinobacillary mastitis
  • Actinobacillus infection
  • Acute abscess of areola
  • Acute abscess of breast
  • Acute mastitis
  • Breast infection
  • Carbuncle of breast
  • Carbuncle of chest wall
  • Carbuncle of pectoral region
  • Cellulitis and abscess of breast
  • Cellulitis and abscess of trunk
  • Cellulitis of breast
  • Cellulitis of pectoral region
  • Coliform mastitis
  • Corynebacterial mastitis
  • Furuncle of breast
  • Furuncle of chest wall
  • Furuncle of pectoral region
  • Infantile streptococcal infection
  • Infection caused by coagulase-negative Staphylococcus
  • Infection caused by Staphylococcus epidermidis
  • Infection of breast in neonate caused by Streptococcus
  • Infective mastitis
  • Intramammary breast abscess
  • Lump of subareolar area of breast
  • Mammary fistula
  • Mycoplasma mastitis
  • Neonatal breast abscess
  • Neonatal infective mastitis
  • Neonatal mastitis
  • Neonatal staphylococcal mastitis
  • Neonatal Staphylococcus aureus mastitis
  • Neonatal Staphylococcus epidermidis mastitis
  • Neonatal streptococcal infection
  • Nonpuerperal abscess of areola
  • Nonpuerperal abscess of breast
  • Nonpuerperal abscess of left breast
  • Nonpuerperal abscess of right breast
  • Nonpuerperal mastitis
  • Nonpuerperal mastitis of left breast
  • Nonpuerperal mastitis of right breast
  • Pseudomonas aeruginosa mastitis
  • Retromammary breast abscess
  • Staphylococcal mastitis
  • Streptococcal mastitis
  • Subareolar breast abscess

Tabular List NotesGuidance

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

Type 1 Excludes

  • breast engorgement of newborn P83.4
  • noninfective mastitis of newborn P83.4

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Abscess(connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
      • breast (acute) (chronic) (nonpuerperal)
        • newborn
    • Mastitis(acute) (diffuse) (nonpuerperal) (subacute)
      • infective
        • newborn
    • Mastitis(acute) (diffuse) (nonpuerperal) (subacute)
      • neonatal (noninfective)
        • infective
    • Newborn(infant) (liveborn) (singleton)
      • mastitis
    • Newborn(infant) (liveborn) (singleton)
      • mastitis
        • infective

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR PNL009
Perinatal infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Uncommon Infant and Newborn Problems

It can be scary when your baby is sick, especially when it is not an everyday problem like a cold or a fever. You may not know whether the problem is serious or how to treat it. If you have concerns about your baby's health, call your health care provider right away.

Read the full article at MedlinePlus

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

Convert P39.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
771.5 Neonatal infec mastitis
Exact Match The mapping is direct, with no qualifiers.

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 P39.0Overview

Is P39.0 (Other infections specific to the perinatal period) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report neonatal infective mastitis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of P39.0?

Under the General Equivalence Mappings, neonatal infective mastitis converts to ICD-9-CM 771.5 (neonatal infec mastitis). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.