Code-level instructions

Includes

hydromicrocephaly
micrencephalon

Excludes 1

Meckel-Gruber syndrome (Q61.9)

Code first

, if applicable, congenital Zika virus disease

Inherited instructions

Chapters 17 · Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0)

Excludes 2

inborn errors of metabolism (E70-E88)

Note

Codes from this chapter are not for use on maternal records

Official index references (19)

Absence(of) (organ or part) (complete or partial) (1)

Absence(of) (organ or part) (complete or partial) › skull bone(congenital) › with › microcephalyDisease index

Agenesis (1)

Agenesis › skull(bone) › with › microcephalyDisease index

Anomaly, anomalous(congenital) (unspecified type) (2)

Deformity (1)

Deformity › skull(acquired) › congenital › with › microcephalyDisease index

Distortion(s) (congenital) (1)

Distortion(s) (congenital) › skull bone(s) NEC › with › microcephalyDisease index

Hydromicrocephaly (1)

HydromicrocephalyDisease index

Hypoplasia, hypoplastic (3)

Hypoplasia, hypoplastic › brainDisease index
Hypoplasia, hypoplastic › cephalicDisease index
Hypoplasia, hypoplastic › skull(bone) › with › microcephalyDisease index

Idiot, idiocy(congenital) (1)

Idiot, idiocy(congenital) › microcephalicDisease index

Imperfect (1)

Imperfect › closure(congenital) › skull › with › microcephalyDisease index

Micrencephalon, micrencephaly (1)

Micrencephalon, micrencephalyDisease index

Microcephalus, microcephalic, microcephaly (1)

Microcephalus, microcephalic, microcephalyDisease index

Microencephalon (1)

MicroencephalonDisease index

Nondevelopment (1)

Nondevelopment › brainDisease index

Oligoencephalon (1)

OligoencephalonDisease index

Undeveloped, undevelopment (2)

Undeveloped, undevelopment › brain(congenital)Disease index
Undeveloped, undevelopment › cerebral(congenital)Disease index

References from other codes (2)

Q75 · Other congenital malformations of skull and face bones

Excludes 1 · microcephaly (Q02)

Q87.88 · CTNNB1 syndrome

Use additional code · microcephaly (Q02)

MS-DRG · 43.1

091 · Other Disorders of Nervous System with MCC
092 · Other Disorders of Nervous System with CC
093 · Other Disorders of Nervous System without CC/MCC
791 · Prematurity with Major Problems
793 · Full Term Neonate with Major Problems

2026-04-01 – 2026-09-30

Code history

Latest recorded change · FY2020

ChangedUnchanged

FY2020

Effective from 2019-10-01

Code-level rules changed

Microcephaly

Billable diagnosis code

CDC/NCHS · FY2020

All editions (19)

All editions	Effective from	Code history
FY2016	2015-10-01	First observed
FY2017	2016-10-01	No tabular change
FY2018	2017-10-01	No tabular change
FY2019	2018-10-01	Code-level rules changed · Inherited rules changed
FY2020	2019-10-01	Code-level rules changed
FY2020 · April	2020-04-01	No tabular change
FY2021	2020-10-01	No tabular change
FY2021 · 01-01	2021-01-01	No tabular change
FY2022	2021-10-01	No tabular change
FY2022 · 04-01	2022-04-01	No tabular change
FY2023	2022-10-01	No tabular change
FY2023 · 04-01	2023-04-01	No tabular change
FY2024	2023-10-01	No tabular change
FY2024 · 04-01	2024-04-01	No tabular change
FY2025	2024-10-01	No tabular change
FY2025 · 04-01	2025-04-01	No tabular change
FY2026	2025-10-01	No tabular change
FY2026 · April	2026-04-01	No tabular change
FY2027	2026-10-01	No tabular change

Historical ICD-9 mappings · 2018

Historical mapping only; not an automatic code substitution.

742.1