2027 ICD-10-CM Diagnosis Code P39.0Neonatal infective mastitis
ICD-10-CM Codes›P00–P96›P35-P39›P39
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Not Chronic
P39.0 is a billable ICD-10-CM diagnosis code for neonatal infective mastitis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 791, 793. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 5 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Perinatal infections.
Code Identity
Code Classification
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 inflammation of breast caused by Staphylococcus
- Neonatal mastitis
- Neonatal mastitis caused by Streptococcus
- 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
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to P39.0: its own notes plus those printed at P39, block P35-P39, and Chapter 16. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- conditions that have their origin in the fetal or perinatal period (before birth through the first 28 days after birth) even if morbidity occurs later
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- asymptomatic human immunodeficiency virus [HIV] infection status (Z21)
- congenital gonococcal infection (A54.-)
- congenital pneumonia (P23.-)
- congenital syphilis (A50.-)
- human immunodeficiency virus [HIV] disease (B20)
- infant botulism (A48.51)
- infectious diseases not specific to the perinatal period (A00-B99, J09, J10.-)
- intestinal infectious disease (A00-A09)
- laboratory evidence of human immunodeficiency virus [HIV] (R75)
- tetanus neonatorum (A33)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify organism or specific infection
Notes
General instructions on how these codes are used.
- Codes from this chapter are for use on newborn records only, never on maternal records
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name P39.0, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming P39.0: they are not reported together with it, unless the two conditions are unrelated.
- N61 Inflammatory disorders of breastneonatal infective mastitis (P39.0)
Excludes2 2
These codes carry an Excludes2 note naming P39.0: its condition is not part of those codes, and both may be reported when the patient has both.
- Chapter 1 (A00-B99) Certain infectious and parasitic diseases
- P00.2 Newborn affected by maternal infectious and parasitic diseases
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Abscess (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic) L02.91
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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.
Code HistoryHistory
Questions About P39.0Overview
What is the ICD-10 code for neonatal infective mastitis?
The ICD-10-CM code for neonatal infective mastitis is P39.0 (sometimes written as P390). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
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, 2026 through September 30, 2027.
What MS-DRG does P39.0 group to?
When neonatal infective mastitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, with relative weights from 4.1073 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.
Is P39.0 a CC or MCC?
CMS lists P39.0 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 5 closely related codes in its exclusion list.
Can P39.0 be reported with P83.4?
Not as a rule. The Excludes1 note on P39.0 lists "breast engorgement of newborn (P83.4)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
