Alphabetic Index FY2027

O24.01

Pre-existing type 1 diabetes mellitus, in pregnancy

FY2027Chapter 15: Pregnancy, childbirth and the puerperium/O20–O29 Other maternal disorders predominantly related to pregnancy

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

O24.01 is a non-billable ICD-10-CM code header for pre-existing type 1 diabetes mellitus, in pregnancy. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are O24.011 Pre-existing type 1 diabetes mellitus, in pregnancy, first trimester; O24.012 Pre-existing type 1 diabetes mellitus, in pregnancy, second trimester; O24.013 Pre-existing type 1 diabetes mellitus, in pregnancy, third trimester and O24.019 Pre-existing type 1 diabetes mellitus, in pregnancy, unspecified trimester. Its coding notes include a Use additional code instruction, 1 Excludes1 entry and 6 Excludes2 entries.

Guidelines tips

From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.

The trimester character comes from the provider's documentation for the current encounter. The unspecified trimester code should rarely be used.

Guidelines I.C.15.a.3; I.C.15.a.5Pregnancy: the trimester characterRead the official text

O24 is sequenced first, followed by the diabetes code from Chapter 4. For gestational diabetes, no other O24 code is used with O24.4.

Guidelines I.C.15.g; I.C.15.iDiabetes in pregnancy and gestational diabetesRead the official text

Use additional code

Add the listed code as a secondary code, if known.

Inherited from O24.0 Pre-existing type 1 diabetes mellitus, in pregnancy, childbirth and the puerperium
  • code from category E10 to further identify any manifestations
Also from chapter/block level (1 note)
Inherited from Chapter 15 Pregnancy, childbirth and the puerperium
  • code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.

Excludes1

Not coded here. The listed conditions generally should not be reported together.

Also from chapter/block level (1 note)
Inherited from Chapter 15 Pregnancy, childbirth and the puerperium
  • supervision of normal pregnancy (Z34.-)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (6 notes)
Inherited from O20–O29 Other maternal disorders predominantly related to pregnancy
  • maternal care related to the fetus and amniotic cavity and possible delivery problems (O30-O48)
  • maternal diseases classifiable elsewhere but complicating pregnancy, labor and delivery, and the puerperium (O98-O99)
Inherited from Chapter 15 Pregnancy, childbirth and the puerperium
  • mental and behavioral disorders associated with the puerperium (F53.-)
  • obstetrical tetanus (A34)
  • postpartum necrosis of pituitary gland (E23.0)
  • puerperal osteomalacia (M83.0)

Notes

Also from chapter/block level (6 notes)
Inherited from Chapter 15 Pregnancy, childbirth and the puerperium
  • 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

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 1 entry

More specific codes under O24.01 4