Gestational Diabetes Definition

Any pregnant person that shows abnormal glucose tolerance that was not present prior to the pregnancy. The American College of Obstetricians and Gynecologists (ACOG) define GDM as "a condition in which carbohydrate intolerance develops during pregnancy.” Preexisting (pregestational) diabetes refers to type 1 or 2 diabetes diagnosed before pregnancy. 

Common Risk Factors: 

• GDM in a prior pregnancy 
• Family history of diabetes 
• Pre-pregnancy BMI ≥30 kg/m2, significant weight gain in early adulthood or between pregnancies, or excessive gestational weight gain during the first 18 to 24 weeks of pregnancy 
• Maternal age >/=35 years of age 

Key Points for Accurate Documentation 

• Specify Diagnosis Clearly 

1. Use the term “Gestational Diabetes Mellitus (GDM)” and indicate if it is diet-controlled (A1) or insulin/medication-controlled (A2). 
2. Avoid vague terms like “borderline diabetes” or “glucose intolerance.” 

• Document Diagnostic Basis 

1. Include OGTT results or note that diagnosis was based on ADA/ACOG criteria (e.g., abnormal 1-hour or 3-hour glucose tolerance test). 

• Capture Clinical Significance 

1. Note any maternal or fetal complications (e.g., polyhydramnios, macrosomia, preeclampsia). 
2. Document treatment plan: diet modification, insulin, oral agents, or glucose monitoring. 

• Differentiate from Pre-existing Diabetes 

1. Confirm that hyperglycemia was first recognized during pregnancy. If diabetes existed before pregnancy, code as pre-gestational diabetes. 

• Postpartum Follow-up 

1. Indicate if postpartum glucose testing or counseling for future diabetes risk was provided. 

Why It Matters: 

Precise documentation supports accurate ICD-10 coding (e.g., O24.41–O24.43), reflects severity of illness, and impacts quality metrics and reimbursement. AHRQ’s Maternity Care Measure Set includes post-partum glucose careening for gestational diabetes patients in Measure 10 – Post-Partum Follow-up and Care Coordination. This measure applies to all patients regardless of age, who gave birth during a 12-month period seen for post-partum care visit before or at 8-weeks of giving birth. There are no exceptions.