Pre-exist type 1 diabetes, in pregnancy, unsp trimester

This code signifies a pregnant patient who has a pre-existing diagnosis of type 1 diabetes mellitus, where the specific trimester of pregnancy is not documented or specified. It indicates that the patient's diabetes was present prior to conception and is now complicating the current pregnancy.

Apply this code when documentation clearly states a patient has type 1 diabetes that predates their current pregnancy, and the medical record does not specify which trimester the encounter or condition relates to. This is appropriate for initial assessments or when trimester information is absent.

• Always sequence this code after the code for the specific obstetric condition (e.g., O99.810 for other specified diseases and conditions complicating pregnancy).
• Avoid using this code if the trimester is clearly documented; instead, select the appropriate trimester-specific code (O24.011, O24.012, O24.013).
• Ensure documentation specifies "type 1" diabetes; do not use for gestational or type 2 diabetes.