5 steps OB/GYN practices should take for the 2027 maternity coding transition

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8/20/2026

If your practice delivers babies, a patient you saw this week may be the reason your cash flow suffers in the first quarter of next year.

On Jan. 1, 2027, the CPT^® maternity code is poised to change substantially. Seventeen codes are deleted, including global codes 59400, 59510 and 59610 — the codes most OB practices have built their billing around for years; 12 codes are added to replace them, organized around four phases of care: antepartum, labor management, delivery and postpartum. Six additional codes are revised, and prenatal and postpartum visits move to standard E/M codes with a TH modifier.^3,4

A global obstetric code can encompass most of a pregnancy and delivery episode, covering nine to 10 months of care. The Jan. 1 effective date therefore runs directly through pregnancies already on your schedule. A patient who established care this spring and delivers in February 2027 will have 2026 antepartum services reported under 2026 rules and 2027 encounters under the new structure.

That is the part practices can act on now. Identify patients whose care crosses the Jan. 1 cutoff, train clinicians and billing staff, and review documentation and payer workflows before claims move under the new structure. Payment will depend on payer implementation.

A second variable: proposed Medicare G-codes

On July 14, 2026, CMS released the Calendar Year 2027 Medicare Physician Fee Schedule proposed rule. CMS is considering 15 new HCPCS G-codes that would preserve a global maternity payment option for Medicare alongside the new CPT^® structure, in an effort to reduce transition disruption.¹

ACOG supports CMS’ inclusion and proposed valuation of the new CPT^® codes but objects to the additional G-code option. In July, ACOG President Camille A. Clare, MD, MPH, CPE, FACOG, warned that maintaining two billing structures would increase administrative burden and confusion for obstetric practices.^2,5

Two points matter for planning. First, the CPT^® changes take effect Jan. 1, but payer billing and payment policies can vary. Second, Medicare covers a limited share of maternity care, so Medicaid and commercial payer implementation may matter more for many practices. Ask those payers how they will adopt the new structure.

As of this writing, the G-codes remain under consideration, not final. CMS typically publishes its final Physician Fee Schedule rule in the fall.

1. Count your transition exposure

Start by putting a number on the patients and revenue potentially affected:

Patients on your current census with a due date on or after Jan. 1, 2027
The same count broken out by payer
Percentage of annual OB revenue currently billed through global codes
Average global fee per delivery across your top three payers

Multiply the transition population by the average global fee for a rough estimate of revenue tied to pregnancies crossing Jan. 1. Bring that figure to every conversation that follows.

2. Get transition guidance from your payers in writing

Ask each of your top payers how they will handle an episode of care that crosses Jan. 1. CPT^® guidance says 2026 antepartum services stay under 2026 rules and 2027 encounters move to E/M reporting, but payers may add their own requirements.³ Specifically:

Will they follow CPT^® calendar-year transition guidance, or apply additional rules?
Is there a published transition policy, and if not, when will one be issued?
How should 2026 antepartum-only services be submitted for patients who continue care in 2027, including 59425 or 59426 when applicable?

Get the answers in writing. Some claims may not be submitted for months, and written payer guidance is easier to rely on in a denial or appeal than a verbal answer.

3. Audit documentation for patients due in 2027

Under the global structure, a light antepartum note carried no financial penalty because payment did not depend on visit-level detail. Under the new structure it does. Every antepartum and postpartum visit has to stand on its own as a documented, billable encounter.

Pull a sample of notes for patients due after Jan. 1 and ask whether each note supports the work performed and, for 2027 office visits, the E/M service reported. Look for the work the global code never required you to document: management of high-risk conditions, mental health screening, genetic counseling, care coordination and changes to the treatment plan.

Where the note falls short, fix the template now. Do not plan on reconstructing documentation later; late entries or addenda should follow your compliance policy and payer rules.

4. Read your payer contracts for deleted code numbers

Contracts and fee schedules frequently reference CPT^® codes by number. Where an agreement names 59400, 59510 or 59610, determine how the payer will update it for dates of service on or after Jan. 1.³ Ask about a revised fee schedule, contract amendment or other approach. Start those conversations this fall rather than waiting until December.

Ask your practice management system, EHR and clearinghouse vendors the same questions. When will the 2027 codes be loaded? What configuration falls to your staff? When can your team test? "Before Jan. 1" is not an answer. Ask for a date.

5. Establish your baseline before the change

Track these OB-specific metrics for the remainder of 2026:

Days in A/R
Clean claim rate
Denial rate
Net collection rate
Reimbursement per delivery, by payer

Without a pre-transition baseline, it will be harder to determine in March whether a first-quarter change reflects the coding transition or an existing revenue-cycle problem. Compare results by payer. That will help you decide whether you fix a workflow, escalate with a payer, or renegotiate a contract.

Conclusion

Some uncertainty will remain until CMS issues the final 2027 fee schedule rule. But the CPT transition takes effect Jan. 1, 2027. If CMS finalizes a Medicare global G-code option, practices may have to manage it alongside the new CPT^® structure for other payers.^1,2,3

Start with the count. Everything else follows from knowing how many patients fall inside the window and who covers them. The practices that do that work now are not only protecting the revenue they have. They are the ones positioned to capture what the new structure finally pays for.