2026 ICD-10-CM Diagnosis Code O36.20X0Maternal care for hydrops fetalis, unspecified trimester, not applicable or unspecified

ICD-10-CM Codes›O00-O9A›O30-O48›O36

ICD-10-CM O36.20X0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O36.20X0 is a billable ICD-10-CM diagnosis code for maternal care for hydrops fetalis, unspecified trimester, not applicable or unspecified. The 7th character 0 shows this applies to a single gestation, or that the affected fetus is not identified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 817 through 819, 831 through 833. The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64). Coders also document this condition as disproportion between fetus and pelvis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Maternal care related to fetal conditions.

Code Identity

ICD-10-CM Code
O36.20X0
Billable Status
Yes — Valid for Submission
Code Describes
Maternal care for hydrops fetalis, unspecified trimester, not applicable or unspecified
Short Description
Maternal care for hydrops fetalis, unsp trimester, unsp
Parent Code
O36.20
Maternal care for hydrops fetalis, unspecified trimester

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO30-O48Maternal care related to the fetus and amniotic cavity and possible delivery problems
CategoryO36Maternal care for other fetal problems
This CodeO36.20X0Maternal care for hydrops fetalis, unspecified trimester, not applicable or unspecified

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O36.20X0.

Maternity diagnoses
The Medicare Code Editor detects inconsistencies in maternity cases by checking a patient's age and any diagnosis on the patient's record. The maternity code edits apply to patients age ange is 9–64 years inclusive (e.g., diabetes in pregnancy, antepartum pulmonary complication).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Disproportion between fetus and pelvis
  • Fetal cystic hygroma
  • Fetal cystic hygroma co-occurrent with hydrops
  • Fetal hydrops causing disproportion
  • Hydrops fetalis
  • Idiopathic hydrops fetalis
  • Non-immune hydrops fetalis

Clinical ClassificationClinical

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

CCSR PRG013
Maternal care related to fetal conditions
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 O36.20X0 to ICD-9-CMHistory

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

ICD-9-CM
656.80 Fet/plac prob NEC-unspec
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 O36.20X0Overview

Is O36.20X0 (Maternal care for hydrops fetalis, unspecified trimester) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report maternal care for hydrops fetalis, unspecified trimester, not applicable or unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character 0 in O36.20X0 mean?

The final character 0 shows the maternal care for hydrops fetalis, unspecified trimester applies to a single gestation, or that the affected fetus cannot be identified.

What MS-DRG does O36.20X0 group to?

When maternal care for hydrops fetalis, unspecified trimester, not applicable or unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 817, 818, 819, 831, 832, 833, with relative weights from 0.5229 to 1.6880 depending on complications. Higher weights mean higher Medicare reimbursement.

Who can O36.20X0 be reported for?

The Medicare Code Editor checks maternal care for hydrops fetalis, unspecified trimester, not applicable or unspecified against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.

What is the ICD-9 equivalent of O36.20X0?

Under the General Equivalence Mappings, maternal care for hydrops fetalis, unspecified trimester, not applicable or unspecified converts to ICD-9-CM 656.80 (fet/plac prob NEC-unspec). 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.