O21.0 – Mild hyperemesis gravidarum

ICD-10-CM 2027 diagnosis code · Other maternal disorders predominantly related to pregnancy

Billable code

ICD-10-CM code O21.0

Code: O21.0 (claims format: O210)
Description: Mild hyperemesis gravidarum
Billable: Yes – valid for HIPAA-covered transactions
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 15. Pregnancy, childbirth and the puerperium (O00-O9A)
Block: O20-O29 Other maternal disorders predominantly related to pregnancy
Parent codes: O21

Notes for O21.0

Applicable to:

Hyperemesis gravidarum, mild or unspecified, starting before the end of the 20th week of gestation

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

Block O20-O29

Excludes2 (not included here):

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)

Index terms for O21.0

Entries in the ICD-10-CM alphabetic index that lead to this code:

Related codes in O21

O21.1 – Hyperemesis gravidarum with metabolic disturbanceBillable
O21.2 – Late vomiting of pregnancyBillable
O21.8 – Other vomiting complicating pregnancyBillable
O21.9 – Vomiting of pregnancy, unspecifiedBillable

Frequently asked questions

What is ICD-10 code O21.0?

O21.0 is the ICD-10-CM code for mild hyperemesis gravidarum, in the block O20-O29 (Other maternal disorders predominantly related to pregnancy).

Is O21.0 a billable code?

Yes. O21.0 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does O21.0 belong to?

It belongs to category O21 – Excessive vomiting in pregnancy.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.