NPI Atlas

O21 – Excessive vomiting in pregnancy

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

Non-billable header

ICD-10-CM code O21

Code: O21 (claims format: O21)
Description: Excessive vomiting in pregnancy
Billable: No – use a more specific code below
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

Billable codes under O21

O21 is a header code and cannot be used on claims. Choose the most specific code:

O21.0 – Mild hyperemesis gravidarumBillable
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

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)

Frequently asked questions

What is ICD-10 code O21?

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

Is O21 a billable code?

No. O21 is a header code with more specific child codes; report one of the billable codes listed above.

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.