2026 ICD-10-CM Diagnosis Code O23.511Infections of cervix in pregnancy, first trimester

ICD-10-CM Codes›O00-O9A›O20-O29›O23

ICD-10-CM O23.511
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

O23.511 is a billable ICD-10-CM diagnosis code for infections of cervix in 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 Inflammatory diseases of female pelvic organs 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
O23.511
Billable Status
Yes — Valid for Submission
Code Describes
Infections of cervix in pregnancy, first trimester
Short Description
Infections of cervix in pregnancy, first trimester
Same as the full description in the CMS dataset.
Parent Code
O23.51
Infection of cervix in pregnancy

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO20-O29Other maternal disorders predominantly related to pregnancy
CategoryO23Infections of genitourinary tract in pregnancy
This CodeO23.511Infections of cervix in pregnancy, first trimester

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O23.511.

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 GEN018
Inflammatory diseases of female pelvic organs
Default principal diagnosis: inpatient No · outpatient No
CCSR PRG028
Other specified complications in pregnancy
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Cervix Disorders

A cervix disorder is a problem with your cervix. The cervix is part of the female reproductive system. It is the lower, narrow end of the uterus (womb), which opens into the vagina (birth canal). The cervix has a small opening that expands during childbirth. It also allows menstrual blood to leave your body.

The full article covers:

  • What is a cervix disorder?
  • Who is more likely to develop cervix disorders?
  • What are the symptoms of cervix disorders?
  • How are cervix disorders diagnosed?
  • What are the treatments for cervix disorders?
  • Can cervix disorders be prevented?

Read the full article at MedlinePlus

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

Convert O23.511 to ICD-9-CMHistory

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

ICD-9-CM
646.61 Gu infection-delivered
Approximate The match is approximate rather than exact.
ICD-9-CM
646.63 Gu infection-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 O23.511Overview

Is O23.511 (Infection of cervix in pregnancy) a billable code?

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

What MS-DRG does O23.511 group to?

When infections of cervix in 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 O23.511 be reported for?

The Medicare Code Editor checks infections of cervix in 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 O23.511?

Under the General Equivalence Mappings, infections of cervix in pregnancy, first trimester converts to ICD-9-CM 646.61 (gu infection-delivered) and 646.63 (gu infection-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.