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ICD-10 Guide
ICD-10 CodesO16.9

O16.9

Billable

Unspecified maternal hypertension, unspecified trimester

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/08/2025

Code Description

ICD-10 O16.9 is a billable code used to indicate a diagnosis of unspecified maternal hypertension, unspecified trimester.

Key Diagnostic Point:

Unspecified maternal hypertension refers to elevated blood pressure in a pregnant woman without a clear diagnosis of the specific type of hypertension, such as gestational hypertension or preeclampsia. This condition can arise at any point during pregnancy and may pose risks to both the mother and fetus, including potential complications such as placental abruption, fetal growth restriction, and preterm birth. The diagnosis of unspecified maternal hypertension is often made when blood pressure readings exceed 140/90 mmHg, but further classification is not determined. Diagnostic workup typically includes monitoring blood pressure, assessing for proteinuria, and evaluating maternal and fetal well-being through ultrasound and laboratory tests. It is crucial for healthcare providers to document the patient's blood pressure readings, any symptoms, and the management plan to ensure appropriate care and coding.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variability in blood pressure readings and their interpretation.
  • Need for differentiation between types of hypertension.
  • Potential for co-existing conditions complicating diagnosis.
  • Documentation requirements for monitoring and follow-up.

Audit Risk Factors

  • Inadequate documentation of blood pressure readings.
  • Failure to specify the trimester of diagnosis.
  • Lack of follow-up documentation for hypertension management.
  • Misclassification of hypertension type.

Specialty Focus

Medical Specialties

Obstetrics and Gynecology

Documentation Requirements

Detailed documentation of blood pressure readings, symptoms, and treatment plans is essential. Providers should also note any relevant history of hypertension.

Common Clinical Scenarios

A pregnant patient presents with elevated blood pressure during a routine visit, requiring monitoring and potential intervention.

Billing Considerations

Coders must ensure that all relevant clinical information is captured to avoid misclassification and ensure appropriate care.

Maternal-Fetal Medicine

Documentation Requirements

High-risk pregnancies necessitate comprehensive documentation, including maternal and fetal assessments, lab results, and management strategies.

Common Clinical Scenarios

A patient with a history of hypertension becomes pregnant and requires close monitoring for complications.

Billing Considerations

High-risk coding requires attention to detail and understanding of the implications of maternal hypertension on fetal health.

Coding Guidelines

Inclusion Criteria

Use O16.9 When
  • According to ICD
  • 10 coding guidelines, maternal hypertension should be coded based on the specific type and trimester
  • 9 is used when the type is unspecified, but coders should strive for specificity when possible

Exclusion Criteria

Do NOT use O16.9 When
No specific exclusions found.

Related ICD-10 Codes

Related CPT Codes

99213CPT Code

Established patient office visit, Level 3

Clinical Scenario

Used for routine follow-up visits for patients with unspecified maternal hypertension.

Documentation Requirements

Document blood pressure readings, symptoms, and management plans.

Specialty Considerations

Obstetricians should ensure that all relevant information is captured for accurate coding.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of maternal conditions, but the use of unspecified codes like O16.9 can lead to challenges in data accuracy and reimbursement.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of maternal conditions, but the use of unspecified codes like O16.9 can lead to challenges in data accuracy and reimbursement.

Reimbursement & Billing Impact

reimbursement.

Resources

Clinical References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Coding & Billing References

  • •
    ICD-10-CM Official Guidelines for Coding and Reporting

Frequently Asked Questions

What should I document when coding O16.9?

Document all blood pressure readings, any symptoms experienced by the patient, and the management plan. Ensure that the trimester is noted and that any follow-up care is documented.