Unsp pre-existing diabetes in pregnancy, third trimester

This code signifies a pregnant patient in her third trimester who has a pre-existing, but unspecified, type of diabetes mellitus. This diagnosis indicates that the specific type of diabetes (e.g., Type 1 or Type 2) was not documented by the provider. The diabetes is complicating the pregnancy.

Apply this code when a pregnant patient in her third trimester has a documented history of diabetes mellitus prior to conception, but the medical record does not specify the type of diabetes. Documentation should clearly state "pre-existing diabetes" and the gestational trimester.

• Ensure the documentation explicitly states "pre-existing" diabetes, not gestational diabetes.
• Confirm the patient is in the third trimester of pregnancy.
• If the type of pre-existing diabetes is specified (e.g., Type 1, Type 2), use the more specific code from the O24.0 or O24.1 subcategories.