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ICD-10-CM 2027 diagnosis code

O91.019Infection of nipple associated with pregnancy, unspecified trimester

✓ Billable / specificMaternity · age 9–64Female only

O91.019 is a valid, billable ICD-10-CM code for infection of nipple associated with pregnancy, unspecified trimester. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Infection of nipple associated w pregnancy, unsp trimester

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About O91.019

O91.019 is the ICD-10-CM diagnosis code for infection of nipple associated with pregnancy, unspecified trimester. It belongs to category O91 (infections of breast associated with pregnancy, the puerperium and lactation), block O85-O92 (complications predominantly related to the puerperium) and chapter 15 (pregnancy, childbirth and the puerperium). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within O91.01, choose O91.019 (unspecified trimester) only when documentation doesn't support a more specific option: first trimester (O91.011), second trimester (O91.012) and third trimester (O91.013).

Use an additional code to identify infection.

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 817 (Other Antepartum Diagnoses with O.R. Procedures with MCC, relative weight 2.0534), DRG 818 (Other Antepartum Diagnoses with O.R. Procedures with CC, relative weight 1.2942), DRG 819 (Other Antepartum Diagnoses with O.R. Procedures without CC/MCC, relative weight 0.7739), DRG 831 (Other Antepartum Diagnoses without O.R. Procedures with MCC, relative weight 1.1558), DRG 832 (Other Antepartum Diagnoses without O.R. Procedures with CC, relative weight 0.7585) and DRG 833 (Other Antepartum Diagnoses without O.R. Procedures without CC/MCC, relative weight 0.5002), in MDC 14 (Pregnancy, Childbirth and the Puerperium), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

The Medicare Code Editor treats this as a maternity diagnosis, expected only for patients age 9 through 64.

It is on the CMS list of diagnoses consistent only with female patients (the sex-conflict edit itself was retired in FY2025).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 675.00 (infections of nipple associated with childbirth, unspecified as to episode of care or not applicable).

Notes that apply from higher levels

Instructions written at a parent level also apply to O91.019.

› From O91 Infections of breast associated with pregnancy, the puerperium and lactation
Use additional code
  • code to identify infection

Broader instructions also apply from O85-O92 Complications predominantly related to the puerperium and Chapter 15: Pregnancy, childbirth and the puerperium.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 675.00Infections of nipple associated with childbirth, unspecified as to episode of care or not applicableapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about O91.019

Is O91.019 billable?

Yes. O91.019 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can O91.019 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict O91.019 as a principal diagnosis.

Is O91.019 a CC or MCC?

No. O91.019 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does O91.019 group to?

O91.019 is used in the MS-DRG v44.0 logic for MS-DRG 817 (Other Antepartum Diagnoses with O.R. Procedures with MCC), MS-DRG 818 (Other Antepartum Diagnoses with O.R. Procedures with CC), MS-DRG 819 (Other Antepartum Diagnoses with O.R. Procedures without CC/MCC), MS-DRG 831 (Other Antepartum Diagnoses without O.R. Procedures with MCC), MS-DRG 832 (Other Antepartum Diagnoses without O.R. Procedures with CC) and MS-DRG 833 (Other Antepartum Diagnoses without O.R. Procedures without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for O91.019?

The CMS General Equivalence Mappings map O91.019 to ICD-9-CM 675.00.