2027 ICD-10-CM Diagnosis Code O21Excessive vomiting in pregnancy

ICD-10-CM Codes›O00-O9A›O20-O29›O21

ICD-10-CM O21
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

O21 is a non-billable ICD-10-CM category code for excessive vomiting in pregnancy, so it cannot be submitted on claims. Use a more specific code from this category instead, such as O21.0, O21.1, O21.2, and O21.8.

Code Identity

ICD-10-CM Code
O21
Billable Status
No — Non-Billable Category
Code Describes
Excessive vomiting in pregnancy
Short Description
Excessive vomiting in pregnancy
Same as the full description in the CMS dataset.
Chapter
O20-O29
Other maternal disorders predominantly related to pregnancy

Code Classification

ChapterO00-O9APregnancy, childbirth and the puerperium
SectionO20-O29Other maternal disorders predominantly related to pregnancy
CategoryO21Excessive vomiting in pregnancy
This CodeO21Excessive vomiting in pregnancy

Specific Coding for Excessive vomiting in pregnancyOverview

Non-specific codes like O21 require more characters. Use one of these billable codes instead:

  • Use O21.0 for Mild hyperemesis gravidarum

  • Use O21.1 for Hyperemesis gravidarum with metabolic disturbance

  • Use O21.2 for Late vomiting of pregnancy

  • Use O21.8 for Other vomiting complicating pregnancy

  • Use O21.9 for Vomiting of pregnancy, unspecified

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to O21: 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.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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.

From Block O20-O29 Other maternal disorders predominantly related to pregnancy applies to 260 codes
  • maternal care related to the fetus and amniotic cavity and possible delivery problems (O30-O48)
  • maternal diseases classifiable elsewhere but complicating pregnancy, labor and delivery, and the puerperium (O98-O99)
From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • mental and behavioral disorders associated with the puerperium (F53.-)
  • obstetrical tetanus (A34)
  • postpartum necrosis of pituitary gland (E23.0)
  • puerperal osteomalacia (M83.0)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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.

From Chapter 15 (O00-O9A) Pregnancy, childbirth and the puerperium applies to 2,481 codes
  • 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, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming O21: they are not reported together with it, unless the two conditions are unrelated.

  • R11 Nausea and vomiting
    excessive vomiting in pregnancy (O21.-)

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.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About O21Overview

What is the ICD-10 code for excessive vomiting in pregnancy?

O21 is the ICD-10-CM category for excessive vomiting in pregnancy, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is O21 (Excessive vomiting in pregnancy) a billable code?

No. This is a category header that groups the codes for excessive vomiting in pregnancy, and headers cannot be submitted on claims. Claims for excessive vomiting in pregnancy need a more specific code from this category, such as O21.0, O21.1, and O21.2.