2027 ICD-10-CM Diagnosis Code O9A.112Malignant neoplasm complicating pregnancy, second trimester

ICD-10-CM Codes›O00-O9A›O94-O9A›O9A

ICD-10-CM O9A.112
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

O9A.112 is a billable ICD-10-CM diagnosis code for malignant neoplasm complicating 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. 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
O9A.112
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm complicating pregnancy, second trimester
Short Description
Malignant neoplasm complicating pregnancy, second trimester
Same as the full description in the CMS dataset.
Parent Code
O9A.11
Malignant neoplasm complicating pregnancy

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO94-O9AOther obstetric conditions, not elsewhere classified
CategoryO9AMaternal malignant neoplasms, traumatic injuries and abuse classifiable elsewhere but complicating pregnancy, childbirth and the puerperium
This CodeO9A.112Malignant neoplasm complicating pregnancy, second trimester

Code EditsBilling

Medicare Code Editor checks that affect claim validity for O9A.112.

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).

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to O9A.112: its own notes plus those printed at O9A.1 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.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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.

From O9A.1 Malignant neoplasm complicating pregnancy, childbirth and the puerperium applies to 6 codes
  • maternal care for benign tumor of corpus uteri (O34.1-)
  • maternal care for benign tumor of cervix (O34.4-)
From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • mental and behavioral disorders associated with the puerperium (F53.-)
  • obstetrical tetanus (A34)
  • postpartum necrosis of pituitary gland (E23.0)
  • puerperal osteomalacia (M83.0)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From O9A.1 Malignant neoplasm complicating pregnancy, childbirth and the puerperium applies to 6 codes
  • code to identify neoplasm
From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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 O9A.112, its category, or a range that includes it.

Excludes2 2

These codes carry an Excludes2 note naming O9A.112: its condition is not part of those codes, and both may be reported when the patient has both.

  • O34.1 Maternal care for benign tumor of corpus uteri
    maternal care for malignant neoplasm of uterus (O9A.1-) names O9A.1-, which includes this code
  • O99.8 Other specified diseases and conditions complicating pregnancy, childbirth and the puerperium
    malignant neoplasm complicating pregnancy, childbirth and the puerperium (O9A.1-) names O9A.1-, which includes this code

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

Tumors and Pregnancy

Tumors during pregnancy are rare, but they can happen. Tumors can be either benign (not cancer) or malignant (cancer). The most common cancers in pregnancy include breast cancer, thyroid cancer, cervical cancer, lymphoma, and melanoma. Cancer itself rarely harms the fetus, and some cancer treatments are safe during pregnancy.

Read the full article at MedlinePlus

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

Convert O9A.112 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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About O9A.112Overview

What is the ICD-10 code for malignant neoplasm complicating pregnancy, second trimester?

The ICD-10-CM code for malignant neoplasm complicating pregnancy, second trimester is O9A.112 (sometimes written as O9A112). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is O9A.112 (Malignant neoplasm complicating pregnancy) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm complicating pregnancy, second trimester on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does O9A.112 group to?

When malignant neoplasm complicating 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.

Who can O9A.112 be reported for?

The Medicare Code Editor checks malignant neoplasm complicating 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.

Does O9A.112 need an additional code?

When the condition applies, yes. The Use Additional Code note at O9A.1, which applies to O9A.112, reads: code to identify neoplasm. The additional code is reported after O9A.112.