2026 ICD-10-CM Diagnosis Code P56.0Hydrops fetalis due to isoimmunization

ICD-10-CM Codes›P00–P96›P50-P61›P56

ICD-10-CM P56.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

P56.0 is a billable ICD-10-CM diagnosis code for hydrops fetalis due to isoimmunization. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as hydrops fetalis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Hemolytic jaundice and perinatal jaundice.

Code Identity

ICD-10-CM Code
P56.0
Billable Status
Yes — Valid for Submission
Code Describes
Hydrops fetalis due to isoimmunization
Short Description
Hydrops fetalis due to isoimmunization
Same as the full description in the CMS dataset.
Parent Code
P56
Hydrops fetalis due to hemolytic disease

Code Classification

ChapterP00–P96Certain conditions originating in the perinatal period
SectionP50-P61Hemorrhagic and hematological disorders of newborn
CategoryP56Hydrops fetalis due to hemolytic disease
This CodeP56.0Hydrops fetalis due to isoimmunization

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Hydrops fetalis
  • Hydrops fetalis due to isoimmunization

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.

    • Dropsy, dropsical
      • newborn due to isoimmunization
    • Hydrops
      • fetalis
        • due to
          • ABO isoimmunization
    • Hydrops
      • fetalis
        • due to
          • isoimmunization (ABO) (Rh)
    • Hydrops
      • fetalis
        • due to
          • Rh incompatibility
    • Hydrops
      • newborn (idiopathic)
        • due to
          • ABO isoimmunization
    • Hydrops
      • newborn (idiopathic)
        • due to
          • isoimmunization (ABO) (Rh)
    • Hydrops
      • newborn (idiopathic)
        • due to
          • Rh incompatibility
    • Isoimmunization NEC
      • newborn
        • with
          • hydrops fetalis

Clinical ClassificationClinical

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

CCSR PNL007
Hemolytic jaundice and perinatal jaundice
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Hydrops Fetalis

    abnormal accumulation of serous fluid in two or more fetal compartments, such as skin; pleura; pericardium; placenta; peritoneum; amniotic fluid. general fetal edema may be of non-immunologic origin, or of immunologic origin as in the case of erythroblastosis fetalis.

  • Hydrops Fetalis

    a condition characterized by fluid accumulation in two or more anatomic compartments in the fetus.

  • Immune Hydrops Fetalis

    fluid accumulation in multiple fetal anatomic cavities attributable to a maternal immune response against fetal blood cell antigens.

  • Non-Immune Hydrops Fetalis

    fluid accumulation in multiple fetal anatomic cavities that is of non-immune origin.

Patient EducationClinical

Edema

Edema means swelling caused by fluid in your body's tissues. It usually occurs in the feet, ankles and legs, but it can involve your entire body.

Read the full article at MedlinePlus

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

Convert P56.0 to ICD-9-CMHistory

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

ICD-9-CM
773.3 Hydrops fetalis:isoimm
Approximate The match is approximate rather than exact.

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 P56.0Overview

Is P56.0 (Hydrops fetalis due to hemolytic disease) a billable code?

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

What is the ICD-9 equivalent of P56.0?

Under the General Equivalence Mappings, hydrops fetalis due to isoimmunization converts to ICD-9-CM 773.3 (hydrops fetalis:isoimm). The mapping is approximate, so confirm the match fits the documentation.

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.