2027 ICD-10-CM Diagnosis Code O23.01Infections of kidney in pregnancy, first trimester
ICD-10-CM Codes›O00-O9A›O20-O29›O23
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Not Chronic
O23.01 is a billable ICD-10-CM diagnosis code for infections of kidney in pregnancy, first trimester. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 817 through 819, 831 through 833. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 263 closely related codes. 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 Urinary tract infections.
This medical diagnosis code is frequently used in OB/GYN medical specialties to designate conditions such maternal disorders related to pregnancy.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for O23.01.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to O23.01: its own notes plus those printed at O23, block O20-O29, and Chapter 15. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- supervision of normal pregnancy (Z34.-)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- gonococcal infections complicating pregnancy, childbirth and the puerperium (O98.2)
- infections with a predominantly sexual mode of transmission NOS complicating pregnancy, childbirth and the puerperium (O98.3)
- syphilis complicating pregnancy, childbirth and the puerperium (O98.1)
- tuberculosis of genitourinary system complicating pregnancy, childbirth and the puerperium (O98.0)
- venereal disease NOS complicating pregnancy, childbirth and the puerperium (O98.3)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.
Notes
General instructions on how these codes are used.
- CODES FROM THIS CHAPTER ARE FOR USE ONLY ON MATERNAL RECORDS, NEVER ON NEWBORN RECORDS
- Codes from this chapter are for use for conditions related to or aggravated by the pregnancy, childbirth, or by the puerperium (maternal causes or obstetric causes)
- Trimesters are counted from the first day of the last menstrual period. They are defined as follows:
- 1st trimester- less than 14 weeks 0 days
- 2nd trimester- 14 weeks 0 days to less than 28 weeks 0 days
- 3rd trimester- 28 weeks 0 days until delivery
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name O23.01, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming O23.01: they are not reported together with it, unless the two conditions are unrelated.
- Block N70-N77 Inflammatory diseases of female pelvic organspregnancy, childbirth and the puerperium (O23.-, O75.3, O85, O86.-) names O23.-, which includes this code
Excludes2 2
These codes carry an Excludes2 note naming O23.01: its condition is not part of those codes, and both may be reported when the patient has both.
- Block N30-N39 Other diseases of the urinary systempregnancy, childbirth and the puerperium (O23.-, O75.3, O86.2-) names O23.-, which includes this code
- O99.8 Other specified diseases and conditions complicating pregnancy, childbirth and the puerperiumgenitourinary infections in pregnancy (O23.-) names O23.-, which includes this code
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Infections and Pregnancy
During pregnancy, some common infections such as the common cold or a skin infection do not usually cause serious problems. Some infections, such as the flu, can be more severe when you're pregnant. But other infections can be harmful to you, your fetus, or both.
The full article covers:
- How can infections affect your pregnancy?
- What infections can be harmful during pregnancy?
- What are the symptoms of an infection during pregnancy?
- What are the treatments for infections during pregnancy?
- Can infections during pregnancy be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert O23.01 to ICD-9-CMHistory
Code HistoryHistory
Questions About O23.01Overview
What is the ICD-10 code for infections of kidney in pregnancy, first trimester?
The ICD-10-CM code for infections of kidney in pregnancy, first trimester is O23.01 (sometimes written as O2301). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is O23.01 (Infections of kidney in pregnancy) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report infections of kidney in pregnancy, first trimester on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does O23.01 group to?
When infections of kidney in pregnancy, first trimester is the principal diagnosis on an inpatient stay, it groups to MS-DRG 833, 832, 831, 819, 818, 817, with relative weights from 0.5000 to 1.7586 depending on complications. Higher weights mean higher Medicare reimbursement.
Is O23.01 a CC or MCC?
CMS lists O23.01 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 263 closely related codes in its exclusion list.
Who can O23.01 be reported for?
The Medicare Code Editor checks infections of kidney 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.
