CurrentPremera BluecrossPolicy N/A

Modifier TH (Obstetrical treatment/services) billing guidance

Defines when Premera recognizes modifier TH appended to professional E/M or home/residence visit codes for antepartum visits and notes exceptions; applies to Premera Blue Cross and affiliated plans.

Policy Summary

PayerPremera Bluecross

PolicyModifier TH (Obstetrical treatment/services) billing guidance

Policy CodePolicy N/A

Change TypeNo material change

Effective DateJan 5, 2012

Next Review DateN/A

Key ActionAppend modifier TH to E&M office visit (99202-99215) or home/residence visit (99341-99350) only for antepartum visits 1-3 and do not append TH to postpartum visits or if the same provider bills a global maternity code.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

antepartum visits 1-3when modifier TH may be appended

4+ visitsrequirement for additional antepartum visits

Alaska exemptgeographic exception

04/02/26archive date noted

professional (CMS-1500)claim form scope

Policy Summary

PayerPremera Bluecross

PolicyModifier TH (Obstetrical treatment/services) billing guidance

Policy CodePolicy N/A

Change TypeNo material change

Effective DateJan 5, 2012

Next Review DateN/A

SourceLink

On This Page

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Modifier TH coverage criteria

Covered when ALL of the following are met:

Modifier TH may be appended to E&M office visit (99202-99215) or home/residence visit (99341-99350) codes only for antepartum visits 1-3.

Antepartum care beyond three visits by the same provider requires submission of antepartum-only codes (59425 or 59426) or an appropriate global maternity procedure code (59400, 59510, 59610, or 59618) when complete maternity care is rendered.

Modifier TH is not appended to any postpartum E&M visit code.

An E&M visit with modifier TH should not be billed by the same provider or provider group that bills a global maternity care code (59400, 59510, 59610, or 59618).

This policy pertains to professional services billed on CMS-1500 or 837P claim forms.

Alaska providers are exempt from this Modifier TH policy.

Policy status: This policy is archived effective April 2, 2026; refer to the Maternity Services policy for related information.

Relevant CPT Codes and Time-Based Selection

Antepartum/postpartum and global maternity codesCPT

59425	Antepartum care only; 4-6 visits
59426	Antepartum care only; 7 or more visits
59430	Postpartum care only (separate procedure)
59400	Routine obstetric care including antepartum care, vaginal delivery (with/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/without episiotomy, and/or forceps) and postpartum care, after previous cesarean delivery
59618	Routine obstetric care including antepartum care, vaginal delivery (with/without episiotomy, and/or forceps) and postpartum care, following attempted vaginal delivery after previous cesarean delivery

E/M office and home/residence visit codesCPT

99202-99205	New patient office visit E/M codes (see policy for individual code descriptors and time thresholds: 99203=30 min, 99204=45 min, 99205=60 min)
99211-99215	Established patient office visit E/M codes (see policy for individual code descriptors and time thresholds: 99212=10 min, 99213=20 min, 99214=30 min, 99215=40 min)
99341-99345	New patient home or residence visit E/M codes (see policy for individual code descriptors and time thresholds: 99341=15 min, 99342=30 min, 99344=60 min, 99345=75 min)
99347-99350	Established patient home or residence visit E/M codes (see policy for individual code descriptors and time thresholds: 99347=20 min, 99348=30 min, 99349=40 min, 99350=60 min)

Time-based selection thresholds

99202When using time for code selection, 15 minutes must be met or exceeded

99203-9920599203: 30 minutes; 99204: 45 minutes; 99205: 60 minutes (time thresholds for new patient office visits)

99211-9921599211: may not require physician; 99212: 10 minutes; 99213: 20 minutes; 99214: 30 minutes; 99215: 40 minutes (established patient office visits)

99341-99345New patient home/residence visits time thresholds: 99341: 15 minutes; 99342: 30 minutes; 99344: 60 minutes; 99345: 75 minutes

99347-99350Established patient home/residence visits time thresholds: 99347: 20 minutes; 99348: 30 minutes; 99349: 40 minutes; 99350: 60 minutes

Billing Actions and Exceptions for Modifier TH

Billing Rule

Billing: When and how to append modifier TH

Append modifier TH to E&M office visit codes (99202-99215) or home/residence visit codes (99341-99350) only for antepartum visits 1–3; do not append TH to any postpartum E&M visit code. Do not bill an E&M visit with modifier TH if the same provider or provider group bills a global maternity care code (59400, 59510, 59610, 59618). For additional antepartum care beyond three visits by the same provider, submit antepartum-only codes (59425 or 59426) or an appropriate global maternity procedure code when complete maternity care is rendered.

Applicable professional claim forms: CMS-1500/837P (policy pertains to professional services).
Modifier TH indicates fewer than the number of antepartum visits designated in code 59425.
Policy archived effective April 2, 2026; refer to Maternity Services policy for related information.

Modifier and Code Definitions

TH (Obstetrical treatment/services)

DefinitionModifier TH = Obstetrical treatment/services appended to E&M office (99202-99215) or home/residence (99341-99350) visit to indicate antepartum visits 1-3

ScopeRecognized only for antepartum visits 1-3; not appended to postpartum E&M visit codes

Billing constraintDo not bill an E&M with modifier TH if the same provider or provider group bills a global maternity code (59400, 59510, 59610, 59618)

59425, 59426 (antepartum care only codes)

59425Antepartum care only; 4-6 visits

59426Antepartum care only; 7 or more visits

59430Postpartum care only (separate procedure)

59400, 59510, 59610, 59618 (global maternity care codes)

59400Routine obstetric care including antepartum care, vaginal delivery and postpartum care

59510Routine obstetric care including antepartum care, cesarean delivery, and postpartum care

59610Routine obstetric care including antepartum care, vaginal delivery after previous cesarean delivery

59618Routine obstetric care including antepartum care following attempted vaginal delivery after previous cesarean delivery

OpenPayer

Modifier TH (Obstetrical treatment/services) billing guidance

When Modifier TH Is Accepted

Relevant CPT Codes and Time-Based Selection

Billing Actions and Exceptions for Modifier TH

Modifier and Code Definitions