O12.00 Gestational edema, unspecified trimester

Billable ICD-10-CM code, FY2026.

MS-DRG index

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

Approximate ICD-9-CM (GEMs)

• 646.10 Edema or excessive weight gain in pregnancy, without mention of hypertension, unspecified as to episode of care or not applicable (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 O12.00

Back-references to O12.0

• Type 2 Excludes: O26.0 Excessive weight gain in pregnancy ("gestational edema (O12.0, O12.2)")
• Type 1 Excludes: R60 Edema, not elsewhere classified ("gestational edema (O12.0-)")

Back-references to O12

• Type 2 Excludes: O99.4 Diseases of the circulatory system complicating pregnancy, childbirth and the puerperium ("hypertensive disorders (O10-O16)")

Nearby codes

• O12 Gestational [pregnancy-induced] edema and proteinuria without hypertension
• O12.0 Gestational edema
• O12.00 Gestational edema, unspecified trimester (this code)
• O12.01 Gestational edema, first trimester
• O12.02 Gestational edema, second trimester
• O12.03 Gestational edema, third trimester
• O12.04 Gestational edema, complicating childbirth
• O12.05 Gestational edema, complicating the puerperium