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    v1.0.28
    OpenPayerBilling CodesOther maternal disorders predominantly related to pregnancyICD-10-CM o21-excessive-vomiting-in-pregnancy
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    ICD-10-CM Code For Excessive Vomiting In Pregnancy: Group Overview

    The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) code group O21 includes diagnoses for excessive vomiting in pregnancy such as hyperemesis gravidarum and other pregnancy-related severe nausea and vomiting that can lead to dehydration and metabolic disturbance. These ICD-10-CM diagnosis codes are used to document maternal conditions that range in severity and to capture clinical complexity related to fluid, electrolyte, and nutritional status during pregnancy. Accurate coding within the ICD-10-CM O21 group supports complete clinical documentation and appropriate reimbursement.

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    ICD-10-CM O21: Excessive Vomiting In Pregnancy Overview

    The ICD-10-CM O21 code group captures excessive vomiting conditions that occur during pregnancy, including hyperemesis gravidarum and other pregnancy-related severe nausea and vomiting. These diagnoses target the maternal gastrointestinal and metabolic effects of pregnancy and potential complications such as dehydration and weight loss. Accurate coding matters for proper clinical documentation and reimbursement because it reflects severity and guides appropriate claim adjudication.

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    When to Use

    Use a code from this group when a pregnant patient presents with persistent or severe vomiting attributable to pregnancy, especially when there is evidence of dehydration, weight loss, or electrolyte imbalance. Select the specific code that reflects documented severity, complications, and any associated maternal metabolic effects.

    ICD-10-CM Codes

    5 rows

    ICD-10-CM CodeDescription
    O21.0Mild hyperemesis gravidarum
    O21.1Hyperemesis gravidarum with metabolic disturbance
    O21.2Late vomiting of pregnancy
    O21.8Other vomiting complicating pregnancy
    O21.9Vomiting of pregnancy, unspecified

    DRG Codes

    6 rows

    DRG CodeDescription
    817Other Antepartum Diagnoses with O.R. Procedures with MCC
    818Other Antepartum Diagnoses with O.R. Procedures with CC
    819Other Antepartum Diagnoses with O.R. Procedures without CC/MCC
    831Other Antepartum Diagnoses without O.R. Procedures with MCC
    832Other Antepartum Diagnoses without O.R. Procedures with CC
    833Other Antepartum Diagnoses without O.R. Procedures without CC/MCC

    Typical Clinical Scenarios

    • A 28-year-old primigravida at 9 weeks gestation presents to the emergency department with persistent nausea and vomiting for several days, unable to tolerate oral fluids and showing signs of dehydration (tachycardia, dry mucous membranes). Laboratory evaluation reveals mild electrolyte imbalance but no ketonuria or weight loss >5% of pre-pregnancy weight, and symptoms are related directly to early pregnancy; a code from this group is assigned for excessive vomiting of pregnancy when outpatient measures have failed. Typical codes: O21.9
    • A 32-year-old pregnant patient in the first trimester has severe, recurrent vomiting with documented ketonemia, significant weight loss (>5% of pre-pregnancy weight), and requires inpatient IV fluids and antiemetic therapy for stabilization. Because the vomiting meets criteria for hyperemesis gravidarum with metabolic disturbance and need for medical intervention, a specific code for hyperemesis is used to capture severity and resource use. Typical codes: O21.0, O21.1
    • A pregnant patient presents for routine prenatal care with intermittent nausea and vomiting that is persistent beyond the first trimester and complicates management of a coexisting condition such as gestational diabetes by interfering with oral intake and medication adherence. A code from this group is assigned to document the pregnancy-related vomiting as a comorbidity affecting pregnancy care and treatment planning. Typical codes: O21.2, O21.8

    Related Codes

    O20-HEMORRHAGE-IN-EARLY-PREGNANCY

    ICD-10-CM Code For Hemorrhage In Early Pregnancy: Group Overview

    O22-VENOUS-COMPLICATIONS-AND-HEMORRHOIDS

    ICD-10-CM Code For Venous Complications And Hemorrhoids In Pregnancy: Group Overview

    O23-INFECTIONS-OF-GENITOURINARY-TRACT

    ICD-10-CM Code For Infections Of Genitourinary Tract In Pregnancy: Group Overview

    O24-DIABETES-MELLITUS-IN-PREGNANCY

    ICD-10-CM Code For Diabetes Mellitus In Pregnancy, Childbirth, And The Puerperium: Group Overview

    O25-MALNUTRITION-IN-PREGNANCY

    ICD-10-CM Code For Malnutrition In Pregnancy Childbirth And The Puerperium: Group Overview

    O26-MATERNAL-CARE-OTHER-CONDITIONS

    ICD-10-CM Code For Maternal Care For Other Conditions Predominantly Related To Pregnancy: Group Overview

    O28-ABNORMAL-ANTENATAL-SCREENING-FINDINGS

    ICD-10-CM Code For Abnormal Findings On Antenatal Screening Of Mother: Group Overview

    O29-COMPLICATIONS-OF-ANESTHESIA

    ICD-10-CM Code For Complications Of Anesthesia During Pregnancy: Group Overview

    Frequently Asked Questions

    References

    1. 1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
    2. 2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
    3. 3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.
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