2026 ICD-10-CM Diagnosis Code O99.330Smoking (tobacco) complicating pregnancy, unspecified trimester

ICD-10-CM Codes›O00-O9A›O94-O9A›O99

ICD-10-CM O99.330
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O99.330 is a billable ICD-10-CM diagnosis code for smoking (tobacco) complicating pregnancy, unspecified 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 Other specified complications in pregnancy and Tobacco-related disorders.

Code Identity

ICD-10-CM Code
O99.330
Billable Status
Yes — Valid for Submission
Code Describes
Smoking (tobacco) complicating pregnancy, unspecified trimester
Short Description
Smoking (tobacco) complicating pregnancy, unsp trimester
Parent Code
O99.33
Tobacco use disorder complicating pregnancy, childbirth, and the puerperium

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO94-O9AOther obstetric conditions, not elsewhere classified
CategoryO99Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium
This CodeO99.330Smoking (tobacco) complicating pregnancy, unspecified trimester

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O99.330.

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.

  • Fetal disorder caused by maternal tobacco via placenta
  • Harmful pattern of use of nicotine
  • Maternal harmful pattern of use of tobacco
  • Maternal tobacco use
  • Maternal tobacco use in pregnancy
  • Nicotine user
  • Nicotine user during pregnancy
  • Reduced smoking during pregnancy
  • Smoking reduced
  • Stopped smoking
  • Stopped smoking during pregnancy
  • Tobacco smoking in mother complicating pregnancy
  • Tobacco use in mother complicating pregnancy

Clinical ClassificationClinical

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

CCSR PRG028
Other specified complications in pregnancy
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR MBD024
Tobacco-related disorders
Default principal diagnosis: inpatient No · outpatient No

Patient EducationClinical

Pregnancy and Substance Use

During pregnancy, there are many things you can do to keep yourself and your baby healthy. They include getting regular prenatal care, eating healthy, and staying active. But it's also very important to avoid substances that could be harmful to you and your baby, such as tobacco, alcohol, and drugs.

Read the full article at MedlinePlus

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

Convert O99.330 to ICD-9-CMHistory

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

ICD-9-CM
649.00 Tobacco use disord-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 O99.330Overview

Is O99.330 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report smoking (tobacco) complicating pregnancy, unspecified trimester on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does O99.330 group to?

When smoking (tobacco) complicating pregnancy, unspecified 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 O99.330 be reported for?

The Medicare Code Editor checks smoking (tobacco) complicating pregnancy, unspecified 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 O99.330?

Under the General Equivalence Mappings, smoking (tobacco) complicating pregnancy, unspecified trimester converts to ICD-9-CM 649.00 (tobacco use disord-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.