2027 ICD-10-CM Diagnosis Code O12.01Gestational edema, first trimester
ICD-10-CM Codes›O00-O9A›O10-O16›O12
- Billable — Valid for Submission
- Not Chronic
O12.01 is a billable ICD-10-CM diagnosis code for gestational edema, 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. 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
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for O12.01.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to O12.01: its own notes plus those printed at 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.
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 O12.01, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming O12.01: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 2
These codes carry an Excludes2 note naming O12.01: its condition is not part of those codes, and both may be reported when the patient has both.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Edema
Edema means swelling caused by fluid in your body's tissues. It usually occurs in the feet, ankles and legs, but it can involve your entire body.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert O12.01 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About O12.01Overview
What is the ICD-10 code for gestational edema, first trimester?
The ICD-10-CM code for gestational edema, first trimester is O12.01 (sometimes written as O1201). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is O12.01 (Gestational edema) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report gestational edema, first trimester on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does O12.01 group to?
When gestational edema, 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.
Who can O12.01 be reported for?
The Medicare Code Editor checks gestational edema, 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 O12.01?
Under the General Equivalence Mappings, gestational edema, first trimester converts to ICD-9-CM 646.11 (edema in preg-delivered), 646.12 (edema in preg-del w p/p), and 646.13 (edema in preg-antepartum). The mapping is approximate, so confirm the match fits the documentation.
