O21.1 Hyperemesis gravidarum with metabolic disturbance

Billable ICD-10-CM code, FY2026.

Applicable to

• 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

MS-DRG index

Defines the logic of DRG(s) 817-819 in MDC 14.

Approximate ICD-9-CM (GEMs)

• 643.13 Hyperemesis gravidarum with metabolic disturbance, antepartum condition or complication (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Maternity diagnoses (age 9 through 64): Age conflict edit. These diagnoses are clinically expected only in patients age 9 through 64.

Code annotations containing back-references to O21.1

Back-references to O21.1

• Type 1 Excludes: E87 Other disorders of fluid, electrolyte and acid-base balance ("electrolyte imbalance associated with hyperemesis gravidarum (O21.1)")

Back-references to O21

• Type 1 Excludes: R11 Nausea and vomiting ("excessive vomiting in pregnancy (O21.-)")

Diagnosis Index entries for O21.1

• Hyperemesis › gravidarum (mild) › with › carbohydrate depletion
• Hyperemesis › gravidarum (mild) › with › dehydration
• Hyperemesis › gravidarum (mild) › with › electrolyte imbalance
• Hyperemesis › gravidarum (mild) › with › metabolic disturbance
• Hyperemesis › gravidarum (mild) › severe (with metabolic disturbance)
• Imbalance › electrolyte › due to hyperemesis gravidarum

Nearby codes

• O21 Excessive vomiting in pregnancy
• O21.0 Mild hyperemesis gravidarum
• O21.1 Hyperemesis gravidarum with metabolic disturbance (this code)
• O21.2 Late vomiting of pregnancy
• O21.8 Other vomiting complicating pregnancy
• O21.9 Vomiting of pregnancy, unspecified