2026 ICD-10-CM Diagnosis Code O99.511Diseases of the respiratory system complicating pregnancy, first trimester

ICD-10-CM Codes›O00-O9A›O94-O9A›O99

ICD-10-CM O99.511
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O99.511 is a billable ICD-10-CM diagnosis code for diseases of the respiratory system complicating pregnancy, first 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.

Code Identity

ICD-10-CM Code
O99.511
Billable Status
Yes — Valid for Submission
Code Describes
Diseases of the respiratory system complicating pregnancy, first trimester
Short Description
Diseases of the resp sys comp pregnancy, first trimester
Parent Code
O99.51
Diseases of the respiratory system complicating pregnancy

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 CodeO99.511Diseases of the respiratory system complicating pregnancy, first trimester

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O99.511.

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 PRG028
Other specified complications in pregnancy
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Breathing Problems

When you're short of breath, it's hard or uncomfortable for you to take in the oxygen your body needs. You may feel as if you're not getting enough air. Sometimes you can have mild breathing problems because of a stuffy nose or intense exercise. But shortness of breath can also be a sign of a serious disease.

Read the full article at MedlinePlus

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

Convert O99.511 to ICD-9-CMHistory

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

ICD-9-CM
648.91 Oth curr cond-delivered
Approximate The match is approximate rather than exact.
ICD-9-CM
648.93 Oth curr cond-antepartum
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 O99.511Overview

Is O99.511 (Diseases of the respiratory system complicating pregnancy) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report diseases of the respiratory system complicating pregnancy, first trimester on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does O99.511 group to?

When diseases of the respiratory system complicating pregnancy, first 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 O99.511 be reported for?

The Medicare Code Editor checks diseases of the respiratory system complicating pregnancy, first 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 O99.511?

Under the General Equivalence Mappings, diseases of the respiratory system complicating pregnancy, first trimester converts to ICD-9-CM 648.91 (oth curr cond-delivered) and 648.93 (oth curr cond-antepartum). 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.