O24.03Pre-existing type 1 diabetes mellitus, in the puerperium

O24.03 is the ICD-10-CM diagnosis code for pre-existing type 1 diabetes mellitus, in the puerperium. 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 billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within O24.0 (pre-existing type 1 diabetes mellitus, in pregnancy, childbirth and the puerperium), O24.03 is specifically for pre-existing type 1 diabetes mellitus, in the puerperium. Related codes cover pregnancy (O24.01) and childbirth (O24.02).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 769 (Postpartum and Post Abortion Diagnoses with O.R. Procedures, relative weight 1.6673) and DRG 776 (Postpartum and Post Abortion Diagnoses without O.R. Procedures, relative weight 0.6721), 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 changed in FY2017 (title revised).

Before ICD-10, this condition was coded in ICD-9-CM as 648.04 (diabetes mellitus of mother, complicating pregnancy, childbirth, or the puerperium, postpartum condition or complication).