2026 ICD-10-CM Diagnosis Code O41.1090Infection of amniotic sac and membranes, unspecified, unspecified trimester, not applicable or unspecified

ICD-10-CM Codes›O00-O9A›O30-O48›O41

ICD-10-CM O41.1090
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O41.1090 is a billable ICD-10-CM diagnosis code for infection of amniotic sac and membranes, unspecified, 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 Maternal intrauterine infection.

Code Identity

ICD-10-CM Code
O41.1090
Billable Status
Yes — Valid for Submission
Code Describes
Infection of amniotic sac and membranes, unspecified, unspecified trimester, not applicable or unspecified
Short Description
Infct of amniotic sac and membrns, unsp, unsp tri, unsp
Parent Code
O41.109
Infection of amniotic sac and membranes, unspecified, unspecified trimester

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO30-O48Maternal care related to the fetus and amniotic cavity and possible delivery problems
CategoryO41Other disorders of amniotic fluid and membranes
This CodeO41.1090Infection of amniotic sac and membranes, unspecified, unspecified trimester, not applicable or unspecified

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O41.1090.

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.

  • Abnormal amniotic fluid
  • Amniotic cavity infection with antenatal problem
  • Clostridial intra-amniotic fetal infection
  • Consistency of liquor - finding
  • Escherichia coli intra-amniotic fetal infection
  • Fetal infection caused by Anaerobic bacterium
  • Fetal infection caused by bacterium
  • Fetal infection caused by Escherichia coli
  • Infection of amniotic cavity
  • Intra-amniotic fetal infection
  • Purulent amniotic fluid

Clinical ClassificationClinical

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

CCSR PRG021
Maternal intrauterine infection
Default principal diagnosis: inpatient Yes · outpatient Yes

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 O41.1090 to ICD-9-CMHistory

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

ICD-9-CM
658.40 Amniotic infection-unsp
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 O41.1090Overview

Is O41.1090 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report infection of amniotic sac and membranes, unspecified, 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 O41.1090 mean?

The final character 0 shows the infection of amniotic sac and membranes, unspecified, unspecified trimester applies to a single gestation, or that the affected fetus cannot be identified.

What MS-DRG does O41.1090 group to?

When infection of amniotic sac and membranes, unspecified, 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 O41.1090 be reported for?

The Medicare Code Editor checks infection of amniotic sac and membranes, unspecified, 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 O41.1090?

Under the General Equivalence Mappings, infection of amniotic sac and membranes, unspecified, unspecified trimester, not applicable or unspecified converts to ICD-9-CM 658.40 (amniotic infection-unsp). 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.