Demystify Prorating in Obstetrics
Use this handy, practical guide for medical coders. One of the most common tasks in obstetrics (OB) coding is prorating antepartum care — it is also one of the most misunderstood tasks. Many coders find themselves confused when a patient transfers care mid-pregnancy, miscarries, or leaves the practice before delivery. The global OB package is designed to simplify billing, but what happens when the global care isn’t truly global? That’s where prorating comes in. What Is Prorating? Prorating is the process of breaking down the global OB package to reflect only the services a provider actually performed. Global OB codes — such as 59400 (Routine obstetric care including antepartum care, vaginal delivery (with or without episiotomy, and/or forceps) and postpartum care) — include approximately 13 antepartum visits, the delivery, and the postpartum visit. When a provider doesn’t complete all components, you should only bill for the portion rendered. When to Prorate Prorating becomes necessary when any of the following occur: Failing to prorate correctly can result in overbilling, claim denials, or even noncompliance issues. See the table below for a quick reference guide: Quick Reference Table for Prorating Antepartum Care Situation How to Bill Key Points < 4 antepartum visits Bill each visit as E/M (99212-99215 est. pt.) Count only OB visits 4-6 antepartum visits 59425 (Antepartum care only; 4-6 visits) Use once for all visits performed by the provider 7+ antepartum visits 59426 (Antepartum care: 7+ visits) Use once for all visits performed by the provider Important Note on Delivery Billing When you prorate a claim and then the provider performs the delivery and will be providing postpartum care, bill the delivery code that includes postpartum care, not the delivery-only code. Examples of common CPT® codes: These codes differ from the global maternity package codes such as 59400 (Routine obstetric care including antepartum care, vaginal delivery (with or without episiotomy, and/or forceps) and postpartum care), 59510 (Routine obstetric care including antepartum care, cesarean delivery, and postpartum care), 59610 (Routine obstetric care including antepartum care, vaginal delivery (with or without episiotomy, and/or forceps) and postpartum care, after previous cesarean delivery), and 59618 (Routine obstetric care including antepartum care, cesarean delivery, and postpartum care, following attempted vaginal delivery after previous cesarean delivery), which include antepartum, delivery, and postpartum care. Use the delivery and postpartum care codes when you are billing for the delivery and postpartum portion and when you are prorating the antepartum care. Example Scenario: A patient transfers into the practice late in pregnancy and has six antepartum visits with the provider before delivery. Since the provider performed part of the antepartum care, performed the delivery, and intends to render the postpartum care, you would bill the appropriate prorated antepartum care code based on the number of visits — 59425 for 4-6 visits — and bill the delivery plus postpartum care code (e.g., 59410 for vaginal delivery only, including postpartum care). Key Takeaway: Use this combination when the provider performs part of the antepartum care and the delivery with postpartum care. This ensures the practice is appropriately reimbursed for all services provided — both the prorated antepartum care and the delivery/postpartum services. Documentation Is Key Clear documentation is your best defense during an audit. Always note the dates of service and number of antepartum visits provided, as well as the reason for discontinuation (transfer, miscarriage, insurance change, and so on). Important note: Always check payer policies for specific billing requirements. Some carriers require a date range for antepartum care, while others want only a single date of service. Submitting a date range when only a single date is required (or vice versa) can result in claim denials and delayed payment. Why This Matters Prorating correctly ensures compliance, prevents overbilling, and protects revenue. It also helps providers and payers clearly understand the scope of care provided. By taking the time to understand prorating, coders can add significant value to their practices while avoiding costly write-offs and keeping claims clean. Nancy Ortiz, CPC, COBGC, CPB, CPCC Additional Resource: Nancy has created a practical OB Prorating Worksheet as a downloadable PDF. If you are interested in receiving a copy, you may email her at saturdaywarriorproject@gmail.com. (A version of this article first appeared in the January 2026 issue of AAPC the Magazine)
(99202-99205 new pt.)
DO not use 59425/59426 for <4 visits
