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ICD-10 Guide
ICD-10 CodesChapter 15: Pregnancy, childbirth and the puerperiumO21

O21

Billable

Excessive vomiting in pregnancy

Chapter 15:Pregnancy, childbirth and the puerperium

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

Code Description

ICD-10 O21 is a billable code used to indicate a diagnosis of excessive vomiting in pregnancy.

Key Diagnostic Point:

Excessive vomiting in pregnancy, commonly referred to as hyperemesis gravidarum, is a severe form of nausea and vomiting that occurs during pregnancy. It is characterized by persistent vomiting that can lead to dehydration, electrolyte imbalances, and nutritional deficiencies. This condition typically arises in the first trimester but can persist throughout pregnancy. Patients may experience weight loss, ketonuria, and an inability to maintain adequate hydration or nutrition. Management often requires hospitalization for intravenous fluids, electrolyte replacement, and nutritional support, including the use of antiemetic medications. The condition can significantly impact the quality of life and may necessitate close monitoring of both maternal and fetal health. Accurate diagnosis and coding are essential for appropriate treatment and reimbursement.

Code Complexity Analysis

Complexity Rating: High

High Complexity

Complexity Factors

  • Differentiating between normal pregnancy nausea and hyperemesis gravidarum
  • Documenting severity and duration of symptoms
  • Identifying associated complications such as dehydration and electrolyte imbalances
  • Understanding the need for nutritional support and IV therapy

Audit Risk Factors

  • Inadequate documentation of symptom severity
  • Failure to document treatment interventions
  • Misclassification of hyperemesis gravidarum severity
  • Lack of follow-up documentation on patient outcomes

Specialty Focus

Medical Specialties

Obstetrics and Gynecology

Documentation Requirements

Documentation must include the frequency and severity of vomiting, weight changes, and any interventions provided.

Common Clinical Scenarios

Patients presenting with severe nausea and vomiting requiring hospitalization for IV fluids and antiemetics.

Billing Considerations

Consideration of the patient's overall health, including pre-existing conditions that may complicate treatment.

Maternal-Fetal Medicine

Documentation Requirements

Detailed documentation of maternal and fetal monitoring, including any complications arising from hyperemesis.

Common Clinical Scenarios

High-risk pregnancies where hyperemesis gravidarum may affect fetal growth and maternal health.

Billing Considerations

Close monitoring of nutritional status and potential impact on fetal development.

Coding Guidelines

Inclusion Criteria

Use O21 When
  • Follow official ICD
  • 10 guidelines for coding excessive vomiting in pregnancy, ensuring accurate documentation of severity and treatment
  • Use additional codes for dehydration and nutritional deficiencies as needed

Exclusion Criteria

Do NOT use O21 When
No specific exclusions found.

Related CPT Codes

99223CPT Code

Initial hospital care, typically 70 minutes or more

Clinical Scenario

Used when a patient with hyperemesis gravidarum is admitted for IV hydration and monitoring.

Documentation Requirements

Document the patient's history, examination findings, and treatment plan.

Specialty Considerations

Obstetricians should ensure that all relevant symptoms and treatments are documented to support the level of care billed.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of hyperemesis gravidarum, improving the ability to capture the severity and associated complications of this condition.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of hyperemesis gravidarum, improving the ability to capture the severity and associated complications of this condition.

Reimbursement & Billing Impact

The transition to ICD-10 has allowed for more specific coding of hyperemesis gravidarum, improving the ability to capture the severity and associated complications of this condition.

Resources

Clinical References

  • •
    American College of Obstetricians and Gynecologists (ACOG) Guidelines

Coding & Billing References

  • •
    American College of Obstetricians and Gynecologists (ACOG) Guidelines

Frequently Asked Questions

What is the difference between O21.0 and O21.1?

O21.0 is used when hyperemesis gravidarum is accompanied by metabolic disturbance, indicating more severe dehydration and electrolyte imbalance, while O21.1 is for cases without metabolic disturbance.