2027 ICD-10-CM Diagnosis Code O24.012Pre-existing type 1 diabetes mellitus, in pregnancy, second trimester
ICD-10-CM Codes›O00-O9A›O20-O29›O24
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Chronic Condition
O24.012 is a billable ICD-10-CM diagnosis code for pre-existing type 1 diabetes mellitus, in pregnancy, second 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 250 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 Diabetes mellitus without complication; Diabetes mellitus, Type 1; and Diabetes or abnormal glucose tolerance complicating pregnancy; childbirth; or the puerperium.
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 O24.012.
Quality Payment Program MeasuresBilling
Medicare quality measures that can apply when O24.012 is part of the patient record.
Diabetes: Glycemic Status Assessment Greater Than 9%
High Priority: YES
Measure Type: Intermediateoutcome
Submission Methods: Claims, Electronic Health Record, Registry
Description: Percentage of patients 18-75 years of age with diabetes who had a glycemic status assessment (hemoglobin A1c [HbA1c] or glucose management indicator [GMI]) > 9.0% during the measurement period.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to O24.012: its own notes plus those printed at O24.0, 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.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code from category E10 to further identify any manifestations
- 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 O24.012, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming O24.012: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 1
These codes carry an Excludes2 note naming O24.012: 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
Diabetes and Pregnancy
If you have diabetes, your blood glucose, or blood sugar, levels are too high. Glucose comes from the foods you eat. A hormone called insulin helps the glucose get into your cells to give them energy. With type 1 diabetes, your body does not make insulin. With type 2 diabetes, your body does not make or use insulin well.
The full article covers:
- What is diabetes?
- What is gestational diabetes?
- Who is more likely to develop gestational diabetes?
- How do I know if I have gestational diabetes?
- How can diabetes affect my pregnancy?
- How can I manage diabetes during pregnancy?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert O24.012 to ICD-9-CMHistory
Code HistoryHistory
Questions About O24.012Overview
What is the ICD-10 code for pre-existing type 1 diabetes mellitus, in pregnancy, second trimester?
The ICD-10-CM code for pre-existing type 1 diabetes mellitus, in pregnancy, second trimester is O24.012 (sometimes written as O24012). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is O24.012 (Pre-existing type 1 diabetes mellitus, in pregnancy) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report pre-existing type 1 diabetes mellitus, in pregnancy, second trimester on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does O24.012 group to?
When pre-existing type 1 diabetes mellitus, in pregnancy, second 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 O24.012 a CC or MCC?
CMS lists O24.012 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 250 closely related codes in its exclusion list.
Who can O24.012 be reported for?
The Medicare Code Editor checks pre-existing type 1 diabetes mellitus, in pregnancy, second trimester against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.
