2026 ICD-10-CM Diagnosis Code O31.8X12Other complications specific to multiple gestation, first trimester, fetus 2

ICD-10-CM Codes›O00-O9A›O30-O48›O31

ICD-10-CM O31.8X12
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O31.8X12 is a billable ICD-10-CM diagnosis code for other complications specific to multiple gestation, first trimester, fetus 2. The 7th character 2 identifies fetus 2 in a multiple gestation pregnancy. 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 Multiple gestation.

Code Identity

ICD-10-CM Code
O31.8X12
Billable Status
Yes — Valid for Submission
Code Describes
Other complications specific to multiple gestation, first trimester, fetus 2
Short Description
Oth comp specific to multiple gest, first trimester, fetus 2
Parent Code
O31.8X1
Other complications specific to multiple gestation, first trimester

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO30-O48Maternal care related to the fetus and amniotic cavity and possible delivery problems
CategoryO31Complications specific to multiple gestation
This CodeO31.8X12Other complications specific to multiple gestation, first trimester, fetus 2

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O31.8X12.

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).

Clinical ClassificationClinical

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

CCSR PRG012
Multiple gestation
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Twins, Triplets, Multiple Births

If you are pregnant with more than one baby, you are far from alone. Multiple births are up in the United States. More women are having babies after age 30 and more are taking fertility drugs. Both boost the chance of carrying more than one baby. A family history of twins also makes multiples more likely.

Read the full article at MedlinePlus

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

Convert O31.8X12 to ICD-9-CMHistory

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

ICD-9-CM
651.81 Multi gestat NEC-deliver
Approximate The match is approximate rather than exact.
ICD-9-CM
651.83 Multi gest NEC-antepart
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 O31.8X12Overview

Is O31.8X12 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other complications specific to multiple gestation, first trimester, fetus 2 on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character 2 in O31.8X12 mean?

The final character 2 identifies the fetus in a multiple gestation pregnancy: this code reports other complications specific to multiple gestation, first trimester for fetus 2.

What MS-DRG does O31.8X12 group to?

When other complications specific to multiple gestation, first trimester, fetus 2 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 O31.8X12 be reported for?

The Medicare Code Editor checks other complications specific to multiple gestation, first trimester, fetus 2 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 O31.8X12?

Under the General Equivalence Mappings, other complications specific to multiple gestation, first trimester, fetus 2 converts to ICD-9-CM 651.81 (multi gestat NEC-deliver) and 651.83 (multi gest NEC-antepart). 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.