2027 ICD-10-CM Diagnosis Code O21.1Hyperemesis gravidarum with metabolic disturbance
ICD-10-CM Codes›O00-O9A›O20-O29›O21
- Billable — Valid for Submission
- Not Chronic
O21.1 is a billable ICD-10-CM diagnosis code for hyperemesis gravidarum with metabolic disturbance. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 817 through 819, 831 through 833. The code is restricted by the Medicare Code Editor to maternity cases (age 9 through 64). Coders also document this condition as hyperemesis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified complications in pregnancy.
This medical diagnosis code is frequently used in OB/GYN medical specialties to designate conditions such maternal disorders related to pregnancy.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for O21.1.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Hyperemesis
- Hyperemesis gravidarum
- Hyperemesis gravidarum before end of 22 week gestation with carbohydrate depletion
- Hyperemesis gravidarum before end of 22 week gestation with dehydration
- Hyperemesis gravidarum before end of 22 week gestation with electrolyte imbalance
- Hyperemesis gravidarum with metabolic disturbance
- Severe hyperemesis gravidarum
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to O21.1: its own notes plus those printed at block O20-O29 and Chapter 15. A note printed at a category, block or chapter applies to every code under it.
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Hyperemesis gravidarum, starting before the end of the 20th week of gestation, with metabolic disturbance such as carbohydrate depletion
- Hyperemesis gravidarum, starting before the end of the 20th week of gestation, with metabolic disturbance such as dehydration
- Hyperemesis gravidarum, starting before the end of the 20th week of gestation, with metabolic disturbance such as electrolyte imbalance
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- supervision of normal pregnancy (Z34.-)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.
Notes
General instructions on how these codes are used.
- CODES FROM THIS CHAPTER ARE FOR USE ONLY ON MATERNAL RECORDS, NEVER ON NEWBORN RECORDS
- Codes from this chapter are for use for conditions related to or aggravated by the pregnancy, childbirth, or by the puerperium (maternal causes or obstetric causes)
- Trimesters are counted from the first day of the last menstrual period. They are defined as follows:
- 1st trimester- less than 14 weeks 0 days
- 2nd trimester- 14 weeks 0 days to less than 28 weeks 0 days
- 3rd trimester- 28 weeks 0 days until delivery
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name O21.1, its category, or a range that includes it.
Excludes1 2
These codes carry an Excludes1 note naming O21.1: they are not reported together with it, unless the two conditions are unrelated.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
carbohydrate depletion O21.1
dehydration O21.1
electrolyte imbalance O21.1
metabolic disturbance O21.1
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Health Problems in Pregnancy
A health problem in pregnancy is any disease or condition that could affect your health or the health of your fetus. Some health problems may make it more likely that you will have a high-risk pregnancy. A high-risk pregnancy is one in which you, your fetus, or both are at higher risk for health problems than in a typical pregnancy.
The full article covers:
- What are health problems in pregnancy?
- What raises my risk for health problems during pregnancy?
- Can chronic health conditions cause problems in pregnancy?
- Can health problems in pregnancy be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert O21.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About O21.1Overview
What is the ICD-10 code for hyperemesis gravidarum with metabolic disturbance?
The ICD-10-CM code for hyperemesis gravidarum with metabolic disturbance is O21.1 (sometimes written as O211). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is O21.1 (Excessive vomiting in pregnancy) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report hyperemesis gravidarum with metabolic disturbance on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does O21.1 group to?
When hyperemesis gravidarum with metabolic disturbance is the principal diagnosis on an inpatient stay, it groups to MS-DRG 833, 832, 831, 819, 818, 817, with relative weights from 0.5000 to 1.7586 depending on complications. Higher weights mean higher Medicare reimbursement.
Who can O21.1 be reported for?
The Medicare Code Editor checks hyperemesis gravidarum with metabolic disturbance against patient demographics: this code is intended for maternity cases (age 9 through 64). Claims outside these limits are flagged as inconsistent.
What is the ICD-9 equivalent of O21.1?
Under the General Equivalence Mappings, hyperemesis gravidarum with metabolic disturbance converts to ICD-9-CM 643.13 (hyperem w metab-antepart). The mapping is approximate, so confirm the match fits the documentation.
