2026 ICD-10-CM Diagnosis Code O40.9XX0Polyhydramnios, unspecified trimester, not applicable or unspecified

ICD-10-CM Codes›O00-O9A›O30-O48›O40

ICD-10-CM O40.9XX0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O40.9XX0 is a billable ICD-10-CM diagnosis code for polyhydramnios, 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). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Polyhydramnios and other problems of amniotic cavity.

Code Identity

ICD-10-CM Code
O40.9XX0
Billable Status
Yes — Valid for Submission
Code Describes
Polyhydramnios, unspecified trimester, not applicable or unspecified
Short Description
Polyhydramnios, unsp trimester, not applicable or unsp
Parent Code
O40.9
Polyhydramnios, unspecified trimester

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO30-O48Maternal care related to the fetus and amniotic cavity and possible delivery problems
CategoryO40Polyhydramnios
This CodeO40.9XX0Polyhydramnios, unspecified trimester, not applicable or unspecified

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O40.9XX0.

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.

  • Abdominal wall edema
  • Fetal disorder due to acute hydramnios
  • Fetal disorder due to chronic hydramnios
  • Fetal disorder due to disorder of amniotic cavity and/or membrane
  • Fetal disorder due to polyhydramnios
  • Finding related to amniotic fluid production
  • Hydrops of allantois
  • Polyhydramnios
  • Polyhydramnios due to maternal disease
  • Polyhydramnios due to placental anomaly

Clinical ClassificationClinical

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

CCSR PRG014
Polyhydramnios and other problems of amniotic cavity
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Polyhydramnios

    a condition of abnormally high amniotic fluid volume, such as greater than 2,000 ml in the last trimester and usually diagnosed by ultrasonographic criteria (amniotic fluid index). it is associated with maternal diabetes mellitus; multiple pregnancy; chromosomal disorders; and congenital abnormalities.

Patient EducationClinical

Health Problems in Pregnancy

A health problem in pregnancy is any disease or condition that could affect your health or the health of your fetus. Some health problems may make it more likely that you will have a high-risk pregnancy. A high-risk pregnancy is one in which you, your fetus, or both are at higher risk for health problems than in a typical pregnancy.

The full article covers:

  • What are health problems in pregnancy?
  • What raises my risk for health problems during pregnancy?
  • Can chronic health conditions cause problems in pregnancy?
  • Can health problems in pregnancy be prevented?

Read the full article at MedlinePlus

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

Convert O40.9XX0 to ICD-9-CMHistory

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

ICD-9-CM
657.00 Polyhydramnios-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 O40.9XX0Overview

Is O40.9XX0 (Polyhydramnios, unspecified trimester) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report polyhydramnios, 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 O40.9XX0 mean?

The final character 0 shows the polyhydramnios, unspecified trimester applies to a single gestation, or that the affected fetus cannot be identified.

What MS-DRG does O40.9XX0 group to?

When polyhydramnios, 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 O40.9XX0 be reported for?

The Medicare Code Editor checks polyhydramnios, 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 O40.9XX0?

Under the General Equivalence Mappings, polyhydramnios, unspecified trimester, not applicable or unspecified converts to ICD-9-CM 657.00 (polyhydramnios-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.