Most Common OB/GYN Billing Mistakes and How to Prevent Them

OB/GYN billing combines global maternity care, surgical services, diagnostic procedures, and high-frequency evaluation and management encounters. Few specialties carry this level of coding overlap and payer scrutiny. Small documentation or coding errors can affect reimbursement across multiple visits, not just a single claim.

In obstetrics and gynecology, billing mistakes often originate in global package misunderstanding, modifier misuse, incomplete documentation, and misaligned procedure coding. Preventing these errors requires structured workflows, specialty-specific knowledge, and consistent audit oversight.

Global Obstetric Package Errors That Disrupt Reimbursement

The global maternity package (CPT 59400, 59510, 59610, 59618) includes antepartum, delivery, and postpartum care. Many billing errors arise from incorrect application of global rules.

Incorrect Use of Global Codes

Common issues include:

• Billing individual E/M visits when the patient qualifies for global billing
• Failing to apply global codes when criteria are met
• Incorrectly separating delivery and postpartum services

Payers expect correct bundling under the global obstetric package. Unbundling global services can trigger denials or post-payment audits.

Miscalculating Antepartum Visit Thresholds

Global billing requires a defined number of antepartum visits. Billing fewer visits separately or exceeding bundled thresholds without documentation creates revenue inconsistency. Clear tracking of:

• Visit count
• Trimester transitions
• Transfer-of-care dates
• High-risk status

Prevents global misapplication.

Transfer-of-Care Errors

When patients transfer providers mid-pregnancy, billing must reflect partial global services (CPT 59425 or 59426). Incorrect full global billing in these cases leads to recoupment risk.

OB/GYN practices must maintain accurate visit logs and care transfer documentation to support partial billing.

Global package errors often affect multiple claims across the pregnancy timeline. These are high-impact billing mistakes.

OB/GYN practices must also reconcile delivery documentation with hospital facility records. When professional claims do not align with institutional reporting of delivery type, attending provider, or date of service, payers may flag discrepancies. Mismatched reporting between hospital and physician claims increases audit probability and reimbursement delay. Cross-verification between facility and professional documentation protects global billing accuracy.

Surgical and Procedural Coding Errors in OB/GYN

Gynecologic procedures involve bundling edits, modifier use, and payer-specific rules. Coding errors frequently occur when multiple procedures are performed during the same encounter.

Incorrect Bundling of Surgical Procedures

Procedures such as hysteroscopy, dilation and curettage (D&C), and laparoscopy may be subject to National Correct Coding Initiative (NCCI) edits. Common mistakes include:

• Failing to apply modifier -59 when appropriate
• Overusing modifier -59 without documentation support
• Billing separately for procedures included in a primary surgical code

Improper bundling results in denials or audit exposure.

Ultrasound and Diagnostic Imaging Errors

OB/GYN practices frequently bill:

• First-trimester ultrasounds
• Detailed anatomy scans
• Transvaginal ultrasounds

Errors occur when:

• Medical necessity is not clearly documented
• Global OB rules are misunderstood
• Imaging is billed without proper interpretation documentation

Ultrasound documentation must include findings, indication, and provider signature to support reimbursement. Payers frequently apply frequency limitations to obstetric ultrasounds, non-stress tests, and repeat imaging. Automated edits evaluate the number of studies performed within defined gestational timeframes. Repeat imaging must be supported by documented medical necessity and updated clinical indication. Without structured tracking of imaging frequency, OB/GYN practices face avoidable denials tied to automated payer edits.

Incomplete Procedure Documentation

Procedure notes must support:

• Indication
• Technique
• Findings
• Complications
• Medical necessity

Incomplete documentation leads to downcoding or denial. Surgical coding accuracy in OB/GYN directly affects reimbursement consistency and audit risk.

E/M Coding and Modifier Conflicts in OB/GYN Practices

OB/GYN practices manage both preventive care and acute issues. Evaluation and management coding overlaps with procedures frequently.

Modifier -25 Misuse

Modifier -25 is used when a significant, separately identifiable E/M service occurs on the same day as a procedure. Common errors:

• Applying modifier -25 automatically
• Failing to document distinct medical decision-making
• Using identical documentation for procedure and E/M justification
  

Payers closely monitor modifier -25 usage in OB/GYN. Unsupported modifier -25 use increases denial rates and audit probability.

Preventive vs Problem-Focused Visit Confusion

Annual well-woman exams often overlap with problem-based visits. Billing errors occur when:

• Problem-oriented E/M is billed without supporting documentation
• Preventive codes are applied when acute issues dominate the visit
• Separate services are not clearly distinguished

Documentation must clearly separate preventive services from problem-focused medical decision-making.

E/M Level Distribution Risk

Higher-level E/M codes (99214, 99215) require documented complexity. Patterns showing disproportionate high-level usage may trigger payer review.

Accurate E/M coding requires clear documentation of:

• History
• Examination
• Medical decision-making complexity
• Time, when applicable

E/M coding consistency protects revenue and reduces audit risk.

Documentation and Compliance Gaps That Increase Denial Exposure

OB/GYN billing is documentation-dependent. Many reimbursement issues originate from incomplete or inconsistent recordkeeping.

Lack of Medical Necessity Detail

Procedures such as colposcopy, endometrial biopsy, and hysteroscopy require clear indication documentation. General diagnosis descriptions are often insufficient. Medical necessity denials frequently result from:

• Missing symptom detail
• Unsupported abnormal findings
• Incomplete diagnostic history

ICD-10 Specificity Errors

OB/GYN diagnosis coding requires trimester specificity, episode-of-care designation, and complication detail.

Common ICD-10 mistakes include:

• Missing trimester specification
• Incorrect pregnancy status coding
• Failure to link complications to pregnancy

Inaccurate ICD-10 coding affects reimbursement and compliance reporting.

Inadequate Internal Audits

Many OB/GYN practices lack structured internal audit programs. Without regular coding review:

• Modifier misuse patterns go unnoticed
• Global package errors repeat
• Denial trends remain unresolved

Routine specialty-specific audits reduce repeated exposure. Denial analysis in OB/GYN should be segmented by category rather than reviewed in aggregate. Global package errors, modifier -25 overuse, trimester coding inaccuracies, and surgical bundling edits represent distinct exposure areas. Tracking denial patterns by CPT category and diagnosis grouping allows targeted corrective action. Specialty-specific denial dashboards improve long-term reimbursement stability.

OB/GYN billing complexity arises from global maternity care, surgical bundling rules, E/M overlaps, and documentation specificity requirements. Many billing mistakes are preventable when structured workflows, coding oversight, and internal audit processes are implemented consistently.

In obstetrics and gynecology, billing accuracy protects reimbursement across multiple encounters, not just individual claims. Preventing common errors requires technical expertise, documentation discipline, and proactive revenue cycle monitoring.

FAQs

1) How often should OB/GYN practices audit global maternity billing?

Global OB billing should be reviewed quarterly, especially in high-volume practices. Transfer-of-care cases and partial antepartum billing require consistent audit validation to prevent recoupment.

2) What is the most common audit trigger in OB/GYN coding?

Modifier -25 usage patterns and high-level E/M distribution are among the most common payer review triggers in OB/GYN practices.

3) Can global maternity billing errors affect postpartum reimbursement?

Yes. Incorrect global application can delay or eliminate reimbursement for postpartum care if delivery coding is misaligned.

4) How do NCCI edits impact gynecologic surgical billing?

National Correct Coding Initiative edits may bundle secondary procedures into primary codes. Improper modifier use or failure to validate bundling rules increases denial and recoupment risk.

5) Are OB ultrasounds included in the global maternity package?

Routine ultrasounds are not automatically included in the global OB package. Coverage depends on payer policy and documented medical necessity.

6) What documentation supports billing a problem-oriented visit during a preventive exam?

Documentation must clearly separate preventive services from distinct medical decision-making, including assessment and treatment of acute or chronic issues.