2026 ICD-10-CM Diagnosis Code O22.33Deep phlebothrombosis in pregnancy, third trimester

ICD-10-CM Codes›O00-O9A›O20-O29›O22

ICD-10-CM O22.33
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O22.33 is a billable ICD-10-CM diagnosis code for deep phlebothrombosis in pregnancy, third trimester. 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 Acute phlebitis; thrombophlebitis and thromboembolism and Other specified complications in pregnancy.

This medical diagnosis code is frequently used in OB/GYN medical specialties to designate conditions such maternal disorders related to pregnancy.

Code Identity

ICD-10-CM Code
O22.33
Billable Status
Yes — Valid for Submission
Code Describes
Deep phlebothrombosis in pregnancy, third trimester
Short Description
Deep phlebothrombosis in pregnancy, third trimester
Same as the full description in the CMS dataset.
Parent Code
O22.3
Deep phlebothrombosis in pregnancy

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO20-O29Other maternal disorders predominantly related to pregnancy
CategoryO22Venous complications and hemorrhoids in pregnancy
This CodeO22.33Deep phlebothrombosis in pregnancy, third trimester

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O22.33.

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 CIR033
Acute phlebitis; thrombophlebitis and thromboembolism
Default principal diagnosis: inpatient No · outpatient No
CCSR PRG028
Other specified complications in pregnancy
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Deep Vein Thrombosis

Deep vein thrombosis, or DVT, is a blood clot that forms in a vein deep in the body. Most deep vein clots occur in the lower leg or thigh. If the vein swells, the condition is called thrombophlebitis. A deep vein thrombosis can break loose and cause a serious problem in the lung, called a pulmonary embolism.

Read the full article at MedlinePlus

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

Convert O22.33 to ICD-9-CMHistory

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

ICD-9-CM
671.31 Deep throm antepar-deliv
Approximate The match is approximate rather than exact.
ICD-9-CM
671.33 Deep vein thromb-antepar
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 O22.33Overview

Is O22.33 (Deep phlebothrombosis in pregnancy) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report deep phlebothrombosis in pregnancy, third trimester on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does O22.33 group to?

When deep phlebothrombosis in pregnancy, third trimester 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 O22.33 be reported for?

The Medicare Code Editor checks deep phlebothrombosis in pregnancy, third trimester 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 O22.33?

Under the General Equivalence Mappings, deep phlebothrombosis in pregnancy, third trimester converts to ICD-9-CM 671.31 (deep throm antepar-deliv) and 671.33 (deep vein thromb-antepar). 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.