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ICD-10-CM 2027 diagnosis code

O24.31Unspecified pre-existing diabetes mellitus in pregnancy

Not billable — use a more specific code

O24.31 is a header code, so it can't be reported by itself. Choose one of the 4 more specific codes beneath it.

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 O24.31

O24.31 is the ICD-10-CM diagnosis code for unspecified pre-existing diabetes mellitus in pregnancy. It belongs to category O24 (diabetes mellitus in pregnancy, childbirth, and the puerperium), block O20-O29 (other maternal disorders predominantly related to pregnancy) and chapter 15 (pregnancy, childbirth and the puerperium). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.

Within O24.3 (unspecified pre-existing diabetes mellitus in pregnancy, childbirth and the puerperium), O24.31 is specifically for unspecified pre-existing diabetes mellitus in pregnancy. Related codes cover childbirth (O24.32) and the puerperium (O24.33).

To report this condition, pick the subcode that matches the documentation: O24.311 (first trimester), O24.312 (second trimester), O24.313 (third trimester) and O24.319 (unspecified trimester).

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

Specific codes under O24.31

Notes that apply from higher levels

Instructions written at a parent level also apply to O24.31.

› From O24.3 Unspecified pre-existing diabetes mellitus in pregnancy, childbirth and the puerperium
Use additional code
  • code (for):
  • from category E11 to further identify any manifestation
  • injectable non-insulin antidiabetic drugs (Z79.85)
  • long-term (current) use of insulin (Z79.4)

Broader instructions also apply from O20-O29 Other maternal disorders predominantly related to pregnancy and Chapter 15: Pregnancy, childbirth and the puerperium.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to O24.31.

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 O24.31

Is O24.31 billable?

No. O24.31 is a header code. Report one of its more specific subcodes instead.