O24.420 Gestational diabetes mellitus in childbirth, diet controlled

Billable ICD-10-CM code, FY2026.

Applies from O24.4 Gestational diabetes mellitus

Applicable to

• Diabetes mellitus arising in pregnancy
• Gestational diabetes mellitus NOS

MS-DRG index

Defines the logic of DRG(s) 998 in MDC 14.

Approximate ICD-9-CM (GEMs)

• 648.81 Abnormal glucose tolerance of mother, delivered, with or without mention of antepartum condition (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 O24.420

Back-references to O24.4

• Type 1 Excludes: E08 Diabetes mellitus due to underlying condition ("gestational diabetes (O24.4-)")
• Type 1 Excludes: E09 Drug or chemical induced diabetes mellitus ("gestational diabetes (O24.4-)")
• Type 1 Excludes: E10 Type 1 diabetes mellitus ("gestational diabetes (O24.4-)")
• Type 1 Excludes: E11 Type 2 diabetes mellitus ("gestational diabetes (O24.4-)")
• Type 1 Excludes: E13 Other specified diabetes mellitus ("gestational diabetes (O24.4-)")
• Type 1 Excludes: O99.81 Abnormal glucose complicating pregnancy, childbirth and the puerperium ("gestational diabetes (O24.4-)")
• Type 1 Excludes: R73.0 Abnormal glucose ("gestational diabetes (O24.4-)")
• Type 1 Excludes: Z86.32 Personal history of gestational diabetes ("gestational diabetes mellitus in current pregnancy (O24.4-)")

Back-references to O24

• Type 2 Excludes: O99.2 Endocrine, nutritional and metabolic diseases complicating pregnancy, childbirth and the puerperium ("diabetes mellitus (O24.-)")
• Type 1 Excludes: R73 Elevated blood glucose level ("diabetes mellitus in pregnancy, childbirth and the puerperium (O24.-)")

Diagnosis Index entries for O24.420

• Delivery (childbirth) (labor) › complicated › by › diabetes › gestational › diet controlled
• Delivery (childbirth) (labor) › complicated › by › gestational › diabetes › diet controlled
• Diabetes, diabetic (mellitus) (sugar) › gestational (in pregnancy) › in childbirth › diet controlled

Nearby codes

• O24.410 Gestational diabetes mellitus in pregnancy, diet controlled
• O24.414 Gestational diabetes mellitus in pregnancy, insulin controlled
• O24.415 Gestational diabetes mellitus in pregnancy, controlled by oral hypoglycemic drugs
• O24.419 Gestational diabetes mellitus in pregnancy, unspecified control
• O24.42 Gestational diabetes mellitus in childbirth
• O24.420 Gestational diabetes mellitus in childbirth, diet controlled (this code)
• O24.424 Gestational diabetes mellitus in childbirth, insulin controlled
• O24.425 Gestational diabetes mellitus in childbirth, controlled by oral hypoglycemic drugs
• O24.429 Gestational diabetes mellitus in childbirth, unspecified control
• O24.43 Gestational diabetes mellitus in the puerperium
• O24.430 Gestational diabetes mellitus in the puerperium, diet controlled