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ICD-10 Guide
ICD-10 CodesO11.9

O11.9

Billable

Pre-existing hypertension with pre-eclampsia, unspecified trimester

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

Code Description

ICD-10 O11.9 is a billable code used to indicate a diagnosis of pre-existing hypertension with pre-eclampsia, unspecified trimester.

Key Diagnostic Point:

Pre-existing hypertension with superimposed pre-eclampsia is a serious condition that occurs when a woman with chronic hypertension develops new-onset hypertension and proteinuria after 20 weeks of gestation. This condition poses significant risks to both the mother and fetus, including increased chances of placental abruption, fetal growth restriction, and preterm birth. Management of this condition requires careful monitoring and may involve medication adjustments, lifestyle modifications, and close surveillance of maternal and fetal well-being. The unspecified trimester designation indicates that the exact timing of the diagnosis within the pregnancy is not documented, which can complicate management strategies. Clinicians must ensure thorough documentation of blood pressure readings, proteinuria assessments, and any interventions undertaken to manage the condition effectively. The complexity of this diagnosis lies in the need for ongoing evaluation and potential escalation of care, including possible hospitalization for severe cases.

Code Complexity Analysis

Complexity Rating: High

High Complexity

Complexity Factors

  • Differentiating between pre-existing hypertension and gestational hypertension.
  • Monitoring for signs of severe pre-eclampsia, which may require immediate intervention.
  • Managing medication regimens that may change throughout the pregnancy.
  • Documenting maternal and fetal assessments accurately to reflect the severity of the condition.

Audit Risk Factors

  • Inadequate documentation of blood pressure readings.
  • Failure to document the onset of proteinuria.
  • Lack of clear treatment plans or management strategies.
  • Insufficient follow-up notes on maternal and fetal health.

Specialty Focus

Medical Specialties

Obstetrics and Gynecology

Documentation Requirements

Detailed records of blood pressure measurements, proteinuria tests, and any medications prescribed.

Common Clinical Scenarios

A patient with a history of hypertension presenting with elevated blood pressure readings and proteinuria during routine prenatal visits.

Billing Considerations

Ensure that all relevant clinical findings are documented to support the diagnosis and management plan.

Maternal-Fetal Medicine

Documentation Requirements

Comprehensive assessments of maternal and fetal health, including ultrasound findings and laboratory results.

Common Clinical Scenarios

High-risk pregnancies requiring close monitoring due to pre-existing hypertension and the development of pre-eclampsia.

Billing Considerations

Collaboration with obstetricians to ensure a multidisciplinary approach to care.

Coding Guidelines

Inclusion Criteria

Use O11.9 When
  • Follow the official ICD
  • CM guidelines for coding obstetric conditions, ensuring accurate documentation of the patient's history, current status, and any interventions performed
  • Specific criteria for pre
  • eclampsia and hypertension must be met for accurate coding

Exclusion Criteria

Do NOT use O11.9 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 pre-existing hypertension and pre-eclampsia.

Documentation Requirements

Document blood pressure readings, symptoms, and any changes in medication.

Specialty Considerations

Ensure that the visit reflects the complexity of managing a high-risk pregnancy.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of obstetric conditions, improving the accuracy of diagnoses and facilitating better management of high-risk pregnancies.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of obstetric conditions, improving the accuracy of diagnoses and facilitating better management of high-risk pregnancies.

Reimbursement & Billing Impact

reimbursement and compliance with payer requirements.

Resources

Clinical References

  • •
    American College of Obstetricians and Gynecologists (ACOG)

Coding & Billing References

  • •
    American College of Obstetricians and Gynecologists (ACOG)

Frequently Asked Questions

What is the difference between pre-existing hypertension and gestational hypertension?

Pre-existing hypertension is a chronic condition that exists before pregnancy, while gestational hypertension develops after 20 weeks of gestation in women without prior hypertension. Accurate documentation is crucial for proper coding.