What O21 covers · when clinicians use it
ICD-10 code O21 identifies Excessive vomiting in pregnancy in the U.S. ICD-10-CM clinical and billing record set. It sits within the ICD-10-CM diagnosis classification, the section that groups related diagnoses so providers, payers, and public-health agencies report them consistently. Clinicians and medical coders apply O21 when an encounter's findings match the Excessive vomiting in pregnancy description, attaching it to the patient record so downstream insurance claims, payer audits, quality reporting, and epidemiological surveillance all reference the same standardized diagnosis. The ICD-10-CM is maintained by the Centers for Medicare & Medicaid Services and the CDC's National Center for Health Statistics, with an updated official code set released each U.S. fiscal year — always verify O21 against the current CMS/CDC release and your payer's documentation guidance before final use. This page summarizes documentation context for O21 and is a coding reference, not clinical, diagnostic, or billing advice.
O21 refers to Excessive vomiting in pregnancy, a range of pregnancy-specific complications including early bleeding, hyperemesis, venous issues, infections, diabetes, malnutrition, abnormal screenings, and anesthesia-related risks during gestation.
Symptoms
- Vaginal bleeding – Seen with hemorrhage in early pregnancy (O20)
- Severe nausea and vomiting – Key feature of excessive vomiting (hyperemesis gravidarum, O21)
- Swelling, varicose veins, or hemorrhoids – Common venous complications (O22)
- Urinary symptoms or fever – Suggestive of genitourinary infections (O23)
- Elevated blood glucose – Characteristic of gestational diabetes (O24)
Diagnosis
Diagnosis of Excessive vomiting in pregnancy involves clinical evaluation, laboratory testing (CBC, glucose levels, urine analysis), ultrasound imaging, antenatal screenings (like serum markers, anomaly scans), and monitoring of maternal and fetal well-being through prenatal visits.
ICD10 Code Usage
ICD10 code O21 is widely used by obstetricians, midwives, maternal-fetal medicine specialists, and anesthesiologists to monitor and manage diverse maternal conditions affecting pregnancy health and outcomes.
Related Codes
- O20 – Hemorrhage in early pregnancy
- O22 – Venous complications and hemorrhoids in pregnancy
- O23 – Infections of genitourinary tract in pregnancy
- O24 – Diabetes mellitus in pregnancy, childbirth, and the puerperium
- O25 – Malnutrition in pregnancy, childbirth and the puerperium
- O26 – Maternal care for other conditions predominantly related to pregnancy
- O28 – Abnormal findings on antenatal screening of mother
- O29 – Complications of anesthesia during pregnancy
FAQs
Q1: What is ICD10 code O21?
A: It refers to Excessive vomiting in pregnancy, documenting complications such as hemorrhage, excessive vomiting, venous disorders, infections, diabetes, and abnormal prenatal findings during pregnancy.
Q2: What causes hemorrhage in early pregnancy (O20)?
A: Common causes include implantation bleeding, subchorionic hematoma, miscarriage, or ectopic pregnancy.
Q3: How serious is hyperemesis gravidarum (O21)?
A: Severe cases can cause dehydration, electrolyte imbalances, weight loss, and hospitalization if not properly managed.
Q4: How are abnormal antenatal findings (O28) handled?
A: They trigger follow-up testing, such as amniocentesis, detailed ultrasounds, or genetic counseling, to evaluate fetal health.
Q5: What anesthesia complications (O29) can occur during pregnancy?
A: Risks include aspiration pneumonia, hypotension, allergic reactions, and adverse effects on maternal or fetal well-being during procedures requiring anesthesia.
Conclusion
ICD10 code O21 helps document and manage Excessive vomiting in pregnancy systematically, ensuring early detection, intervention, and optimized maternal-fetal health throughout pregnancy and childbirth.