CommercialBilling CodesHigh impact
Global Obstetrics/New Maternity Services Codes
Blue Cross Blue Shield of Vermont·VT · OB-GYN, Family Medicine, General Practice·Coding
Effective date
Sep 1, 2026
We identified it
Aug 4, 2026
Summary
Beginning September 1, 2026, prenatal care billing transitions from global obstetric codes (59425, 59426) to E/M codes with modifier -TH appended, requiring Z34A ICD-10-CM codes to document gestational age. This change anticipates the 2027 maternity services code transition and applies to first prenatal visits and all subsequent antepartum visits. Claims must meet current E/M coding rules with documented medical decision making or time-based support.
Action Required
By September 1, 2026: (1) Billing team must update claims processing system and encounter templates to require modifier -TH appended to all E/M codes for maternity/prenatal care services on or after this date. (2) Implement requirement for Z34A ICD-10-CM codes (4th character required for gestational age) on first prenatal visit claims. (3) Update provider documentation templates and EMR reminders to ensure medical records support medical decision making or time-based E/M coding per current CPT guidelines. (4) Stop billing global maternity codes 59425 and 59426 for dates of service on/after September 1, 2026; continue using these codes only for services prior to September 1, 2026. (5) Train billing staff and providers on new requirements and validation procedures. Failure to comply will result in claim denials or recoupment for improperly coded prenatal services.