What Is the 2027 CPT Maternity Code Restructure?
Effective January 1, 2027, the AMA is deleting the global obstetric package codes (59400, 59510, 59610, 59618, and related codes) and replacing them with a framework that bills each phase of maternity care separately: antepartum visits as individual E/M services, labor management as a distinct billable phase, delivery using updated procedure codes, and postpartum care as separate E/M visits. This is the largest structural change to OB/GYN billing in decades. Practices that do not prepare their billing workflows before January will face claim denials, revenue gaps, and documentation failures on every pregnancy that spans the transition.
Global codes are ending: CPT codes 59400, 59510, 59430, and their variants are being deleted. Practices can no longer bill a single code for the full pregnancy package starting January 1, 2027.
Each visit is billed separately: Antepartum visits use E/M codes (99202 through 99215) with modifier TH to identify the visit as maternity care. Postpartum visits are billed with separate E/M codes. Delivery codes remain but are restructured.
ACOG recommends transitioning by September 2026: ACOG urges practices and health plans to begin using E/M codes for antepartum visits by September 1, 2026, to avoid administrative burdens and billing errors for pregnancies that extend into 2027.
What Is Changing and Why
Since the 1990s, obstetric billing in the United States has operated under a global payment model. A single CPT code, such as 59400 for a routine vaginal delivery, bundled all antepartum visits, the delivery itself, and postpartum care into one payment. The practice submitted one code and received one reimbursement for the entire pregnancy episode.
In April 2026, the AMA CPT Editorial Panel approved a comprehensive restructuring developed in collaboration with ACOG that replaces this bundled model with four distinct billing phases: antepartum care, labor management, delivery, and postpartum care. Each phase is billed using its own set of codes. The change takes effect January 1, 2027.
The restructuring is designed to produce several improvements. Practices that provide more intensive prenatal care for high-risk patients can now bill for that complexity rather than absorbing it into the same global code used for routine pregnancies. Postpartum care can extend beyond two visits, aligning with the expanded Medicaid postpartum coverage that 48 states plus DC now provide for a full 12 months. And the granular data generated by per-visit billing will support maternal health outcomes research that bundled billing made impossible.
However, the administrative impact is significant. Under global billing, one pregnancy generated one primary claim. Under unbundled billing, one pregnancy generates approximately 15 to 20 separate claims across the antepartum, delivery, and postpartum phases. That is a 15-fold increase in claim volume per patient, and every claim needs correct coding, documentation, and modifier application.
How Does Unbundled Maternity Billing Work?
Under the new framework, each phase of maternity care has its own billing approach.
Antepartum visits: Each prenatal visit is billed as an individual E/M service using CPT codes 99202 through 99215, based on the complexity of the encounter. ACOG recommends appending modifier TH to each antepartum E/M code to identify it as a maternity care service. A typical uncomplicated pregnancy involves 12 to 14 antepartum visits, each of which becomes a separately billable encounter.
Labor management: The new framework creates distinct codes for labor management, recognizing the physician’s work during the labor phase as a separately billable service. This replaces the labor component that was previously absorbed into the global code.
Delivery: Delivery codes are restructured but remain procedure-based. The delivery itself (vaginal or cesarean) continues to be billed with an appropriate CPT code, but without the antepartum and postpartum components that were previously bundled in.
Postpartum care: Postpartum visits are billed separately using E/M codes. The current code 59430 (postpartum care only) is being deleted. Instead, each postpartum visit is an individual E/M encounter. This allows practices to bill for more than the two postpartum visits that the traditional global period covered, which aligns with ACOG’s recommendation for comprehensive postpartum care and the 12-month Medicaid postpartum coverage now available in most states.
What OB/GYN Practices Must Do Before January 2027
ACOG recommends that the transition begin no later than September 1, 2026. Here is the preparation checklist.
- Start billing antepartum visits as E/M services now. For patients whose pregnancies will extend into 2027, begin using E/M codes with modifier TH for antepartum visits in 2026. Once the global codes are deleted on January 1, 2027, retroactive bundling will not be possible. Transitioning early ensures continuity for pregnancies that span both years.
- Update your EHR documentation templates. Each antepartum visit must now support the E/M level billed. Documentation needs to reflect the medical decision-making complexity, time spent, or both, at the individual visit level. Templates built for global package documentation will not capture the detail needed for per-visit E/M billing.
- Verify payer readiness. Contact every commercial payer and Medicaid managed care plan in your mix to confirm they will accept E/M codes with modifier TH for antepartum visits, that they recognize the new labor management codes, and that they will process unbundled postpartum visits. Some state Medicaid programs may have additional reporting requirements.
- Retrain your coding and billing team. The skill set shifts from global package management to high-volume E/M coding with obstetric modifiers. Coders who have been selecting one global code per pregnancy need to learn per-visit E/M level selection, modifier TH application, and the new labor management and delivery code structure.
- Model the revenue impact. The AMA designed the restructure to be budget-neutral in aggregate, but the impact varies by practice type. High-risk practices and maternal-fetal medicine specialists may see revenue increases because complex antepartum visits are now individually valued. Routine-volume practices may see stable revenue with higher administrative costs. Model your specific payer mix and patient acuity to project the change.
- Prepare for CMS G-code decisions. The CMS 2027 PFS proposed rule (July 14, 2026) includes proposed G-codes for obstetric billing that overlap with the AMA CPT restructure. ACOG has urged CMS to adopt the new CPT codes and not implement separate G-codes, which would create a dual-code system. Monitor the final rule (expected late October) for the CMS decision on this issue.
The transition from global to unbundled obstetric billing increases claim volume per pregnancy by 15 times and requires new coding workflows, documentation templates, and payer verification. If your billing team is not already preparing for this change, a specialized OB/GYN billing partner can manage the transition while your practice focuses on patient care.
Pregnancies That Span 2026 and 2027
One of the most complex billing scenarios the restructure creates is the pregnancy that begins under the global billing model in 2026 and continues into 2027 when the global codes no longer exist.
ACOG’s guidance is direct: begin using E/M codes for antepartum visits during 2026 for patients whose deliveries will fall in 2027. This means practices should identify every patient currently in their second or third trimester and begin billing their antepartum visits as individual E/M services with modifier TH, even though the global codes are still technically available in 2026.
The alternative, continuing to bill under the global model in 2026 and then switching mid-pregnancy in 2027, creates a situation where the antepartum visits billed globally in 2026 cannot be retroactively unbundled. The practice absorbs those visits into a partial global payment and then bills the remaining 2027 visits individually, which may result in a lower total reimbursement than either a full global or a full unbundled approach would have produced.
For billing teams, this means the transition effectively starts in the fall of 2026, not January 2027. Every pregnancy entering the third trimester in Q4 2026 needs to be evaluated for the billing approach that maximizes reimbursement and avoids coding conflicts at the year boundary.
Common Mistakes During Billing Model Transitions
| Mistake | Impact | Prevention |
|---|---|---|
| Waiting until January 2027 to transition | Pregnancies spanning both years create coding conflicts and revenue gaps | Begin E/M billing with modifier TH for antepartum visits by September 2026 |
| Using global-era documentation for E/M billing | Documentation does not support the E/M level billed; denials and downcodes | Update EHR templates now for per-visit E/M documentation requirements |
| Not verifying payer acceptance of new codes | Claims denied; payer systems not yet configured for unbundled OB billing | Contact each payer before September to confirm E/M + TH modifier acceptance |
| No revenue modeling before transition | Practice discovers revenue shortfall or surplus only after Q1 2027 close | Model projected per-pregnancy revenue under unbundled codes using current patient volume |
Frequently Asked Questions
When do the global OB codes stop working?
Global obstetric codes including 59400, 59510, 59610, 59618, and 59430 are being deleted effective January 1, 2027. Claims submitted with these codes for dates of service on or after that date will be denied. The delivery-only codes remain but are restructured.
What modifier is used for antepartum E/M visits?
ACOG recommends appending HCPCS modifier TH to the E/M code to identify the visit as maternity care. This modifier differentiates the antepartum visit from a standard E/M visit and helps payers correctly adjudicate the claim under maternity billing rules.
Will unbundled billing increase or decrease OB/GYN revenue?
The AMA designed the restructure to be budget-neutral in aggregate. High-risk and maternal-fetal medicine practices are best positioned to see revenue increases because complex antepartum visits are now individually valued. Standard-volume routine practices may see roughly stable revenue but with higher administrative costs from the increased claim volume.
What about the CMS proposed G-codes for obstetric billing?
The CMS 2027 PFS proposed rule (July 14, 2026) includes proposed G-codes for obstetric billing that would exist alongside the AMA CPT restructure. ACOG has urged CMS to adopt the new CPT codes instead and not implement separate G-codes. The final CMS decision is expected in the final rule, typically published in late October or early November.
How many claims does one pregnancy generate under unbundled billing?
Approximately 15 to 20 separate claims per pregnancy, up from one primary global code. This includes 12 to 14 antepartum visits, labor management, delivery, and postpartum visits, each billed as an individual encounter. The claim volume increase requires billing infrastructure that can handle the higher throughput.
Can a billing company manage this transition?
Yes. A specialized OB/GYN billing company handles the coding transition, payer verification, documentation workflow updates, and the 15-fold increase in claim volume that unbundled billing creates. OB/GYN Bill Co, powered by Billing Service Quotes, connects obstetric practices with billing partners that have direct experience in maternity care coding and the revenue cycle management capacity to absorb the transition.
Next Steps
Identify all patients currently in their second or third trimester whose deliveries will fall in 2027 and begin billing their antepartum visits as E/M services with modifier TH.
Contact every commercial payer and Medicaid plan in your mix to confirm acceptance of E/M codes with modifier TH for antepartum visits by September 1, 2026.
If your billing team cannot handle the 15-fold increase in claim volume and the coding complexity of the transition, get matched with a specialized OB/GYN billing partner. Matching through OB/GYN Bill Co is free and typically takes 30 minutes.
The global OB billing model that has been in place for decades ends January 1, 2027. The practices that prepare now will capture full revenue under the new framework. The ones that wait will lose money on every pregnancy that crosses the transition. OB/GYN Bill Co, powered by Billing Service Quotes, connects obstetric and gynecology practices with vetted billing companies that specialize in maternity care coding, E/M documentation, and the revenue cycle management infrastructure this transition demands. More than 2,000 providers have been matched across all 50 states, with billing rates starting at 6%. Getting matched is free.
