2026 ICD-10-CM Diagnosis Code Q02Microcephaly

ICD-10-CM Codes›Q00-Q99›Q00-Q07›Q02

ICD-10-CM Q02
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q02 is a billable ICD-10-CM diagnosis code for microcephaly. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nervous system congenital anomalies.

Code Identity

ICD-10-CM Code
Q02
Billable Status
Yes — Valid for Submission
Code Describes
Microcephaly
Chapter
Q00-Q07
Congenital malformations of the nervous system

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ00-Q07Congenital malformations of the nervous system
CategoryQ02Microcephaly
This CodeQ02Microcephaly

Present on Admission (POA)Billing

Q02 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Achalasia microcephaly syndrome
  • Achalasia of esophagus
  • Agammaglobulinemia, microcephaly, craniosynostosis, severe dermatitis syndrome
  • Amish lethal microcephaly
  • Anonychia
  • Anonychia with microcephaly syndrome
  • Aphalangy and syndactyly with microcephaly syndrome
  • Athetoid cerebral palsy
  • Atrophy of cerebellar vermis
  • Autosomal dominant primary microcephaly
  • Autosomal recessive chorioretinopathy and microcephaly syndrome
  • Autosomal recessive primary microcephaly
  • Bilateral congenital cataract of eyes
  • Body height below reference range
  • Brachycephaly
  • CIMDAG syndrome
  • Cleft palate, large ears, small head syndrome
  • Colobomatous microphthalmia
  • Congenital achalasia of esophagus
  • Congenital atrophy of optic nerve
  • Congenital conduction defect
  • Congenital hypoplasia of brain
  • Congenital ichthyosis, microcephalus, tetraplegia syndrome
  • Congenital intrauterine infection-like syndrome
  • Congenital kyphoscoliosis
  • Congenital kyphosis
  • Congenital microcephaly
  • Congenital microcephaly, severe encephalopathy, progressive cerebral atrophy syndrome
  • Congenital microencephaly
  • Congenital nephritis
  • Congenital porencephaly
  • Congenital prognathism
  • Congenital radioulnar synostosis
  • Cortical blindness
  • Diffuse atrophy of cerebellum
  • Diffuse atrophy of cerebrum
  • Diffuse cerebral and cerebellar atrophy, intractable seizures, progressive microcephaly syndrome
  • Disorder of cholesterol metabolism
  • Disorder of cholesterol synthesis
  • Disorder of serine metabolism
  • DONSON-related microcephaly, short stature, limb abnormalities spectrum
  • Dyskinetic cerebral palsy
  • Early-onset progressive diffuse brain atrophy, microcephaly, muscle weakness, optic atrophy syndrome
  • Epilepsy, microcephaly, skeletal dysplasia syndrome
  • Epiphyseal dysplasia, microcephalus, nystagmus syndrome
  • Extrasystoles, short stature, hyperpigmentation, microcephaly syndrome
  • Feingold syndrome
  • Fetal malformation of central nervous system
  • Fetal microcephaly
  • Galloway Mowat syndrome
  • Global brain atrophy
  • Goldberg Shprintzen megacolon syndrome
  • Hadziselimovic syndrome
  • Hereditary cerebellar atrophy
  • Hydranencephaly
  • Hydromicrocephaly
  • Hypernatremia
  • Hypogonadotropic hypogonadism, severe microcephaly, sensorineural hearing loss, dysmorphism syndrome
  • Inborn error of amino acid metabolism
  • Inborn error of lipoprotein metabolism
  • Infantile cerebral and cerebellar atrophy with postnatal progressive microcephaly
  • Inherited disorder of folate metabolism
  • Insulin resistance
  • Intellectual disability, early-onset cataract, microcephaly syndrome
  • Intellectual disability, feeding difficulties, developmental delay, microcephaly syndrome
  • Kawashima Tsuji syndrome
  • MacDermot Winter syndrome
  • Macrotia
  • Malabsorption of glucose
  • Mandibulofacial dysostosis with microcephaly
  • Marfanoid physique
  • MECP2 related disorder
  • MEHMO syndrome
  • Microcephalic cortical malformations, short stature due to RTTN deficiency
  • Microcephalic osteodysplastic dysplasia Saul Wilson type
  • Microcephalic osteodysplastic primordial dwarfism type II
  • Microcephalic osteodysplastic primordial dwarfism types I and III
  • Microcephalic primordial dwarfism Alazami type
  • Microcephalic primordial dwarfism Dauber type
  • Microcephalic primordial dwarfism due to ZNF335 deficiency
  • Microcephalic primordial dwarfism Montreal type
  • Microcephalic primordial dwarfism Toriello type
  • Microcephalic primordial dwarfism, insulin resistance syndrome
  • Microcephalus cardiomyopathy syndrome
  • Microcephalus cleft palate syndrome
  • Microcephalus with albinism and digital anomaly syndrome
  • Microcephalus with brachydactyly and kyphoscoliosis syndrome
  • Microcephalus with cardiac defect and lung malsegmentation syndrome
  • Microcephalus, brain defect, spasticity, hypernatremia syndrome
  • Microcephalus, cerebellar hypoplasia, cardiac conduction defect syndrome
  • Microcephalus, complex motor and sensory axonal neuropathy syndrome
  • Microcephalus, glomerulonephritis, marfanoid habitus syndrome
  • Microcephalus, hypergonadotropic hypogonadism, short stature syndrome
  • Microcephalus, lymphedema, chorioretinopathy syndrome
  • Microcephaly
  • Microcephaly with cervical spine fusion anomaly
  • Microcephaly with simplified gyral pattern
  • Microcephaly, congenital cataract, psoriasiform dermatitis syndrome
  • Microcephaly, corpus callosum and cerebellar vermis hypoplasia, facial dysmorphism, intellectual disability syndrome
  • Microcephaly, corpus callosum hypoplasia, intellectual disability, facial dysmorphism syndrome
  • Microcephaly, facial dysmorphism, ocular anomalies, multiple congenital anomalies syndrome
  • Microcephaly, hypogammaglobulinemia, abnormal immunity syndrome
  • Microcephaly, intellectual disability, sensorineural hearing loss, epilepsy, abnormal muscle tone syndrome
  • Microcephaly, normal intelligence and immunodeficiency
  • Microcephaly, polymicrogyria, corpus callosum agenesis syndrome
  • Microcephaly, seizure, intellectual disability, heart disease syndrome
  • Microcephaly, short stature, intellectual disability, facial dysmorphism syndrome
  • Microcephaly, thin corpus callosum, intellectual disability syndrome
  • Microcephaly-capillary malformation syndrome
  • Microcornea
  • Microlissencephaly
  • Mild intellectual disability
  • MMEP syndrome
  • Mowat-Wilson syndrome
  • MTHFS-related developmental delay, microcephaly, short stature, epilepsy syndrome
  • NDE1-related microhydranencephaly
  • Neonatal diabetes mellitus
  • Neonatal encephalopathy
  • Nijmegen breakage syndrome-like disorder
  • Non-spastic cerebral palsy
  • Osteodysplastic primordial dwarfism
  • Osteogenesis imperfecta, perinatal lethal
  • Osteogenesis imperfecta, recessive perinatal lethal, with microcephaly AND cataracts
  • Osteoplastic dysplasia
  • Permanent neonatal diabetes mellitus
  • Porencephaly, microcephaly, bilateral congenital cataract syndrome
  • Postnatal microcephaly, infantile hypotonia, spastic diplegia, dysarthria, intellectual disability syndrome
  • Primary microcephaly, epilepsy, permanent neonatal diabetes syndrome
  • Primary microcephaly, mild intellectual disability, young-onset diabetes syndrome
  • Progressive microcephaly, seizures, cortical blindness, developmental delay syndrome
  • Progressive microcephaly, seizures, cortical blindness, developmental delay with combined immunodeficiency due to DIAPH1 mutation
  • Psoriasiform dermatitis
  • PYCR2-related microcephaly, progressive leukoencephalopathy
  • Radioulnar synostosis with microcephaly and scoliosis syndrome
  • Second cranial nerve finding
  • Secondary microcephaly
  • Seemanova Lesny syndrome
  • SETD2-related microcephaly, severe intellectual disability, multiple congenital anomalies syndrome
  • Severe combined immunodeficiency with low T- and B-cell numbers
  • Severe combined immunodeficiency, microcephaly, growth retardation, sensitivity to ionizing radiation syndrome
  • Severe feeding difficulties, failure to thrive, microcephaly due to ASXL3 deficiency syndrome
  • Severe intellectual disability, progressive postnatal microcephaly, midline stereotypic hand movements syndrome
  • Severe microbrachycephaly, intellectual disability, athetoid cerebral palsy syndrome
  • Severe neonatal onset encephalopathy with microcephaly
  • Severe X-linked intellectual disability Gustavson type
  • Spastic tetraplegia
  • Spastic tetraplegia, thin corpus callosum, progressive postnatal microcephaly syndrome
  • Sporadic fetal brain disruption sequence
  • Steroid-resistant nephrotic syndrome
  • THOC6-related developmental delay-microcephaly-facial dysmorphism syndrome
  • USP18 deficiency
  • X-linked colobomatous microphthalmia, microcephaly, intellectual disability, short stature syndrome
  • X-linked microcephaly, growth retardation, prognathism, cryptorchidism syndrome

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Includes

  • hydromicrocephaly
  • micrencephalon

Code First

  • , if applicable, congenital Zika virus disease

Type 1 Excludes

  • Meckel-Gruber syndrome Q61.9

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Absence(of) (organ or part) (complete or partial)
      • skull bone (congenital)
        • with
          • microcephaly
    • Agenesis
      • skull (bone)
        • with
          • microcephaly
    • Anomaly, anomalous(congenital) (unspecified type)
      • bone
        • skull
          • with
            • microcephaly
    • Anomaly, anomalous(congenital) (unspecified type)
      • skull
        • with
          • microcephaly
    • Deformity
      • skull (acquired)
        • congenital
          • with
            • microcephaly
    • Distortion(s) (congenital)
      • skull bone (s) NEC
        • with
          • microcephaly
    • Hydromicrocephaly
    • Hypoplasia, hypoplastic
      • brain
    • Hypoplasia, hypoplastic
      • cephalic
    • Hypoplasia, hypoplastic
      • skull (bone)
        • with
          • microcephaly
    • Idiot, idiocy(congenital)
      • microcephalic
    • Imperfect
      • closure (congenital)
        • skull
          • with
            • microcephaly
    • Micrencephalon, micrencephaly
    • Microcephalus, microcephalic, microcephaly
    • Microencephalon
    • Nondevelopment
      • brain
    • Oligoencephalon
    • Undeveloped, undevelopment
      • brain (congenital)
    • Undeveloped, undevelopment
      • cerebral (congenital)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MAL004
Nervous system congenital anomalies
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Microcephaly

    a congenital abnormality in which the cerebrum is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (desk reference for neuroscience, 2nd ed.)

  • Nijmegen Breakage Syndrome

    a chromosome instability syndrome resulting from a defective response to dna double-strand breaks. in addition to characteristic facies and microcephaly, patients have a range of findings including radiosensitivity, immunodeficiency, increased cancer risk, and growth retardation. causative mutations occur in the nbs1 gene, located on human chromosome 8q21. nbs1 codes for nibrin, the key regulator protein of the r/m/n (rad50/mre11/nbs1) protein complex which senses and mediates cellular response to dna damage caused by ionizing radiation.

  • Hydranencephaly

    a congenital condition where the greater portions of the cerebral hemispheres and corpus striatum are replaced by csf and glial tissue. the meninges and the skull are well formed, which is consistent with earlier normal embryogenesis of the telencephalon. bilateral occlusions of the internal carotid arteries in utero is a potential mechanism. clinical features include intact brainstem reflexes without evidence of higher cortical activity. (menkes, textbook of child neurology, 5th ed, p307)

  • Insulin Resistance

    diminished effectiveness of insulin in lowering blood sugar levels: requiring the use of 200 units or more of insulin per day to prevent hyperglycemia or ketosis.

  • Metabolic Syndrome

    a cluster of symptoms that are risk factors for cardiovascular diseases and type 2 diabetes mellitus. the major components of metabolic syndrome include abdominal obesity; atherogenic dyslipidemia; hypertension; hyperglycemia; insulin resistance; a proinflammatory state; and a prothrombotic (thrombosis) state.

  • Hypernatremia

    excessive amount of sodium in the blood. (dorland, 27th ed)

  • Cerebrum

    derived from telencephalon, cerebrum is composed of a right and a left hemisphere. each contains an outer cerebral cortex and a subcortical basal ganglia. the cerebrum includes all parts within the skull except the medulla oblongata, the pons, and the cerebellum. cerebral functions include sensorimotor, emotional, and intellectual activities.

  • GAIA Level 1 Postnatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 1 Postnatally Diagnosed Congenital Microcephaly|Level 1 Postnatally Diagnosed Congenital Microcephaly

    gaia level 1 postnatally diagnosed congenital microcephaly is defined by three criteria: first, a live birth, stillbirth, or spontaneous or therapeutic abortion of at least 24 weeks gestational age (ga), with ga assessed by either a certain last menstrual period (lmp) date with confirmatory 1st trimester (less than 14 weeks) or 2nd trimester ultrasound (us) scan or intrauterine insemination (iui) or embryo transfer date; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile as assessed by ga and gender, using appropriate, standardized reference charts for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, the measurement is taken either between 24 and 36 hours after birth or at the end of the pregnancy. important notice: the nci thesaurus contains biomedical terminologies that nci does not own or control. this concept contains gender-related content that does not comply with executive order 14168.

  • GAIA Level 1a Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 1a Prenatally Diagnosed Congenital Microcephaly|Level 1a Prenatally Diagnosed Congenital Microcephaly

    gaia level 1a prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga) based on certain last menstrual period (lmp) date with confirmatory 1st trimester or 2nd trimester ultrasound (us) scan or intrauterine insemination (iui) or embryo transfer date; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile according to fetal us examination, using appropriate, standardized reference charts according to ga and gender for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24-36 weeks); third, confirmation of microcephaly (i.e., hc 2 sd below the mean or less than 3%) in the fetus by either at least one additional us after 24 weeks that occurs at least one week after the first us, or confirmation of microcephaly by hc measurement with a standard tape measure at either birth or autopsy. important notice: the nci thesaurus contains biomedical terminologies that nci does not own or control. this concept contains gender-related content that does not comply with executive order 14168.

  • GAIA Level 1b Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 1b Prenatally Diagnosed Congenital Microcephaly|Level 1b Prenatally Diagnosed Congenital Microcephaly

    gaia level 1b prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga) based on uncertain last menstrual period (lmp) date with a 2nd trimester ultrasound (us) scan; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile according to fetal us examination, using appropriate, standardized reference charts according to ga and gender for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24-36 weeks); third, confirmation of microcephaly (i.e., hc 2 sd below the mean or less than 3%) in the fetus by either at least one additional us after 24 weeks that occurs at least one week after the first us, or confirmation of microcephaly by hc measurement with a standard tape measure at either birth or autopsy. important notice: the nci thesaurus contains biomedical terminologies that nci does not own or control. this concept contains gender-related content that does not comply with executive order 14168.

  • GAIA Level 2 Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 2 Prenatally Diagnosed Congenital Microcephaly|Level 2 Prenatally Diagnosed Congenital Microcephaly

    gaia level 2 prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga) based on last menstrual period (lmp) date with fundal height and no confirmatory first or second trimester ultrasound (us) scan; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile according to fetal us examination, using appropriate, standardized reference charts according to ga and gender for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks) with femur length and abdominal circumference concordant with ga assessment; third, confirmation of microcephaly (i.e., hc 2 sd below the mean or less than 3%) in the fetus by either at least one additional us after 24 weeks that occurs at least one week after the first us, or confirmation of microcephaly by hc measurement with a standard tape measure at either birth or autopsy. important notice: the nci thesaurus contains biomedical terminologies that nci does not own or control. this concept contains gender-related content that does not comply with executive order 14168.

  • GAIA Level 2a Postnatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 2a Postnatally Diagnosed Congenital Microcephaly|Level 2a Postnatally Diagnosed Congenital Microcephaly

    gaia level 2a postnatally diagnosed congenital microcephaly is defined by three criteria: first, a live birth, stillbirth, or spontaneous or therapeutic abortion of at least 24 weeks gestational age (ga), with ga assessed by either a certain last menstrual period (lmp) date with confirmatory 1st trimester (less than 14 weeks) or 2nd trimester ultrasound (us) scan or intrauterine insemination (iui) or embryo transfer date; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile as assessed by ga and gender, using appropriate, standardized reference charts for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, one of the following requirements is met: a) the measurement is taken within the first 24 hours after birth or at the end of the pregnancy taking into consideration the molding of the head; or b) the measurement is taken greater than 36 hours and up to 6 weeks after birth or the end of the pregnancy with no apparent post-natal insult resulting in microcephaly. important notice: the nci thesaurus contains biomedical terminologies that nci does not own or control. this concept contains gender-related content that does not comply with executive order 14168.

  • GAIA Level 2b Postnatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 2b Postnatally Diagnosed Congenital Microcephaly|Level 2b Postnatally Diagnosed Congenital Microcephaly

    gaia level 2b postnatally diagnosed congenital microcephaly is defined by three criteria: first, a live birth, stillbirth, or spontaneous or therapeutic abortion of at least 24 weeks gestational age (ga), with ga assessed based on uncertain lmp with 2nd trimester ultrasound (us) scan; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile as assessed by ga and gender, using appropriate, standardized reference charts for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, one of the following requirements is met: a) the measurement is taken within the first 24 hours after birth or at the end of the pregnancy taking into consideration the molding of the head; or b) the measurement is taken greater than 36 hours and up to 6 weeks after birth or the end of the pregnancy with no apparent post-natal insult resulting in microcephaly. important notice: the nci thesaurus contains biomedical terminologies that nci does not own or control. this concept contains gender-related content that does not comply with executive order 14168.

  • GAIA Level 3a Postnatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 3a Postnatally Diagnosed Congenital Microcephaly|Level 3a Postnatally Diagnosed Congenital Microcephaly

    gaia level 3a postnatally diagnosed congenital microcephaly is defined by three criteria: first, a live birth, stillbirth, or spontaneous or therapeutic abortion of at least 24 weeks ga based on lmp without confirmatory 1st or 2nd trimester ultrasound; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile as assessed by ga and gender, using appropriate, standardized reference charts for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, the measurement is taken up to 6 weeks after birth or end of pregnancy, with no apparent post-natal insult resulting in microcephaly. important notice: the nci thesaurus contains biomedical terminologies that nci does not own or control. this concept contains gender-related content that does not comply with executive order 14168.

  • GAIA Level 3a Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 3a Prenatally Diagnosed Congenital Microcephaly|Level 3a Prenatally Diagnosed Congenital Microcephaly

    gaia level 3a prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga), with ga based on certain last menstrual period (lmp) date, with confirmatory first or second trimester ultrasound (us) scan, or uncertain lmp with second trimester ultrasound, intrauterine insemination (iui) or embryo transfer date; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile according to fetal us examination, using appropriate, standardized reference charts according to ga and gender for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, no confirmation of microcephaly with any additional us or by hc measurement at either birth or autopsy. important notice: the nci thesaurus contains biomedical terminologies that nci does not own or control. this concept contains gender-related content that does not comply with executive order 14168.

  • GAIA Level 3b Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 3b Prenatally Diagnosed Congenital Microcephaly|Level 3b Prenatally Diagnosed Congenital Microcephaly

    gaia level 3b prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga), with ga based on certain or uncertain last menstrual period (lmp) date, with fundal height and no confirmatory first or second trimester ultrasound (us) scan, or uncertain lmp with second trimester ultrasound, intrauterine insemination (iui) or embryo transfer date; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile according to fetal us examination, using appropriate, standardized reference charts according to ga and gender for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, no confirmation of microcephaly with any additional us or by hc measurement at either birth or autopsy. important notice: the nci thesaurus contains biomedical terminologies that nci does not own or control. this concept contains gender-related content that does not comply with executive order 14168.

  • GAIA Level 4 Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 4 Prenatally Diagnosed Congenital Microcephaly|Level 4 Prenatally Diagnosed Congenital Microcephaly

    gaia level 4 prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga), with ga based on certain last menstrual period (lmp) date with confirmatory first or second trimester ultrasound (us) scan, or uncertain lmp with second trimester ultrasound, intrauterine insemination (iui), or embryo transfer, or certain or uncertain lmp with fundal height and no confirmatory first or second trimester scan; second, hc 2 sd below mean or less than 3 percentile according to fetal us scan using appropriate standardized reference charts according to ga and gender for the population (e.g., who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24-36 weeks); third, hc at birth or autopsy is in the normal range using appropriate standardized reference charts according to ga and gender for the population, which means that this is not a case of prenatally diagnosed congenital microcephaly. important notice: the nci thesaurus contains biomedical terminologies that nci does not own or control. this concept contains gender-related content that does not comply with executive order 14168.

  • Multinucleated Neurons, Anhydramnios, Renal Dysplasia, Cerebellar Hypoplasia and Hydranencephaly|MARCH

    a lethal autosomal recessive condition caused by mutation(s) in the cep55 gene, encoding centrosomal protein of 55 kda. it is characterized by renal dysplasia, anhydramnios, hydrancephaly, cerebellar hypoplasia, and multinucleated neurons in remaining brain tissue.

  • Grade 1 Hypernatremia, CTCAE|Grade 1 Hypernatremia

    >uln - 150 mmol/l

  • Grade 2 Hypernatremia, CTCAE|Grade 2 Hypernatremia

    >150 - 155 mmol/l; intervention initiated

  • Grade 3 Hypernatremia, CTCAE|Grade 3 Hypernatremia

    >155 - 160 mmol/l; hospitalization indicated

  • Congenital Microcephaly

    a congenital developmental disorder in which the circumference of the head is smaller than normal for the person's age and sex.

  • GAIA Congenital Microcephaly Level of Diagnostic Certainty Terminology|Global Alignment of Immunization safety Assessment in pregnancy Congenital Microcephaly Level of Diagnostic Certainty Terminology

    a subset of terminology related to congenital microcephaly, developed by the global alignment of immunization safety assessment in pregnancy consortium to aid in monitoring and improving fetal and maternal outcomes.

  • GAIA Congenital Microcephaly Level of Diagnostic Certainty|Congenital Microcephaly Level of Diagnostic Certainty|Global Alignment of Immunization safety Assessment in pregnancy Congenital Microcephaly Level of Diagnostic Certainty

    a classification of maternal and fetal outcomes relating to congenital microcephaly, developed by the global alignment of immunization safety assessment in pregnancy, based on the extent to which the diagnosis has been confirmed.

  • GAIA Level 1 Postnatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 1 Postnatally Diagnosed Congenital Microcephaly|Level 1 Postnatally Diagnosed Congenital Microcephaly

    gaia level 1 postnatally diagnosed congenital microcephaly is defined by three criteria: first, a live birth, stillbirth, or spontaneous or therapeutic abortion of at least 24 weeks gestational age (ga), with ga assessed by either a certain last menstrual period (lmp) date with confirmatory 1st trimester (less than 14 weeks) or 2nd trimester ultrasound (us) scan or intrauterine insemination (iui) or embryo transfer date; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile as assessed by ga and gender, using appropriate, standardized reference charts for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, the measurement is taken either between 24 and 36 hours after birth or at the end of the pregnancy.

  • GAIA Level 1a Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 1a Prenatally Diagnosed Congenital Microcephaly|Level 1a Prenatally Diagnosed Congenital Microcephaly

    gaia level 1a prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga) based on certain last menstrual period (lmp) date with confirmatory 1st trimester or 2nd trimester ultrasound (us) scan or intrauterine insemination (iui) or embryo transfer date; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile according to fetal us examination, using appropriate, standardized reference charts according to ga and gender for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24-36 weeks); third, confirmation of microcephaly (i.e., hc 2 sd below the mean or less than 3%) in the fetus by either at least one additional us after 24 weeks that occurs at least one week after the first us, or confirmation of microcephaly by hc measurement with a standard tape measure at either birth or autopsy.

  • GAIA Level 1b Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 1b Prenatally Diagnosed Congenital Microcephaly|Level 1b Prenatally Diagnosed Congenital Microcephaly

    gaia level 1b prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga) based on uncertain last menstrual period (lmp) date with a 2nd trimester ultrasound (us) scan; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile according to fetal us examination, using appropriate, standardized reference charts according to ga and gender for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24-36 weeks); third, confirmation of microcephaly (i.e., hc 2 sd below the mean or less than 3%) in the fetus by either at least one additional us after 24 weeks that occurs at least one week after the first us, or confirmation of microcephaly by hc measurement with a standard tape measure at either birth or autopsy.

  • GAIA Level 2 Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 2 Prenatally Diagnosed Congenital Microcephaly|Level 2 Prenatally Diagnosed Congenital Microcephaly

    gaia level 2 prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga) based on last menstrual period (lmp) date with fundal height and no confirmatory first or second trimester ultrasound (us) scan; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile according to fetal us examination, using appropriate, standardized reference charts according to ga and gender for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks) with femur length and abdominal circumference concordant with ga assessment; third, confirmation of microcephaly (i.e., hc 2 sd below the mean or less than 3%) in the fetus by either at least one additional us after 24 weeks that occurs at least one week after the first us, or confirmation of microcephaly by hc measurement with a standard tape measure at either birth or autopsy.

  • GAIA Level 2a Postnatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 2a Postnatally Diagnosed Congenital Microcephaly|Level 2a Postnatally Diagnosed Congenital Microcephaly

    gaia level 2a postnatally diagnosed congenital microcephaly is defined by three criteria: first, a live birth, stillbirth, or spontaneous or therapeutic abortion of at least 24 weeks gestational age (ga), with ga assessed by either a certain last menstrual period (lmp) date with confirmatory 1st trimester (less than 14 weeks) or 2nd trimester ultrasound (us) scan or intrauterine insemination (iui) or embryo transfer date; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile as assessed by ga and gender, using appropriate, standardized reference charts for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, one of the following requirements is met: a) the measurement is taken within the first 24 hours after birth or at the end of the pregnancy taking into consideration the molding of the head; or b) the measurement is taken greater than 36 hours and up to 6 weeks after birth or the end of the pregnancy with no apparent post-natal insult resulting in microcephaly.

  • GAIA Level 2b Postnatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 2b Postnatally Diagnosed Congenital Microcephaly|Level 2b Postnatally Diagnosed Congenital Microcephaly

    gaia level 2b postnatally diagnosed congenital microcephaly is defined by three criteria: first, a live birth, stillbirth, or spontaneous or therapeutic abortion of at least 24 weeks gestational age (ga), with ga assessed based on uncertain lmp with 2nd trimester ultrasound (us) scan; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile as assessed by ga and gender, using appropriate, standardized reference charts for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, one of the following requirements is met: a) the measurement is taken within the first 24 hours after birth or at the end of the pregnancy taking into consideration the molding of the head; or b) the measurement is taken greater than 36 hours and up to 6 weeks after birth or the end of the pregnancy with no apparent post-natal insult resulting in microcephaly.

  • GAIA Level 3a Postnatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 3a Postnatally Diagnosed Congenital Microcephaly|Level 3a Postnatally Diagnosed Congenital Microcephaly

    gaia level 3a postnatally diagnosed congenital microcephaly is defined by three criteria: first, a live birth, stillbirth, or spontaneous or therapeutic abortion of at least 24 weeks ga based on lmp without confirmatory 1st or 2nd trimester ultrasound; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile as assessed by ga and gender, using appropriate, standardized reference charts for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, the measurement is taken up to 6 weeks after birth or end of pregnancy, with no apparent post-natal insult resulting in microcephaly.

  • GAIA Level 3a Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 3a Prenatally Diagnosed Congenital Microcephaly|Level 3a Prenatally Diagnosed Congenital Microcephaly

    gaia level 3a prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga), with ga based on certain last menstrual period (lmp) date, with confirmatory first or second trimester ultrasound (us) scan, or uncertain lmp with second trimester ultrasound, intrauterine insemination (iui) or embryo transfer date; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile according to fetal us examination, using appropriate, standardized reference charts according to ga and gender for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, no confirmation of microcephaly with any additional us or by hc measurement at either birth or autopsy.

  • GAIA Level 3b Postnatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 3b Postnatally Diagnosed Congenital Microcephaly|Level 3b Postnatally Diagnosed Congenital Microcephaly

    gaia level 3b postnatally diagnosed congenital microcephaly is defined by two criteria: first, a live birth, stillbirth, or spontaneous or therapeutic abortion, and second, the case meets criteria for microcephaly using a validated algorithm: 1 inpatient diagnosis or 2 outpatient diagnoses or 1 outpatient diagnosis and death in first year using the following diagnostic codes icd-9-cm code 742.1 or icd-10-cm code q02.

  • GAIA Level 3b Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 3b Prenatally Diagnosed Congenital Microcephaly|Level 3b Prenatally Diagnosed Congenital Microcephaly

    gaia level 3b prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga), with ga based on certain or uncertain last menstrual period (lmp) date, with fundal height and no confirmatory first or second trimester ultrasound (us) scan, or uncertain lmp with second trimester ultrasound, intrauterine insemination (iui) or embryo transfer date; second, a head circumference (hc) measurement either 2 standard deviations (sd) below the mean or less than the third percentile according to fetal us examination, using appropriate, standardized reference charts according to ga and gender for the population (e.g. who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24 to 36 weeks); third, no confirmation of microcephaly with any additional us or by hc measurement at either birth or autopsy.

  • GAIA Level 4 Postnatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 4 Postnatally Diagnosed Congenital Microcephaly|Level 4 Postnatally Diagnosed Congenital Microcephaly

    gaia level 4 postnatally diagnosed congenital microcephaly is defined by two criteria: first, a live birth, stillbirth, or spontaneous or therapeutic abortion; second, a diagnosis of congenital microcephaly based on either a physical inspection without head circumference (hc) measurement, or an icd-9-cm or icd-10-cm code that does not meet the validated algorithm criteria used in the case definition for gaia level 3 postnatally diagnosed congenital microcephaly.

  • GAIA Level 4 Prenatally Diagnosed Congenital Microcephaly|Global Alignment of Immunization safety Assessment in pregnancy Level 4 Prenatally Diagnosed Congenital Microcephaly|Level 4 Prenatally Diagnosed Congenital Microcephaly

    gaia level 4 prenatally diagnosed congenital microcephaly is defined by three criteria: first, the fetus is at least 24 weeks gestational age (ga), with ga based on certain last menstrual period (lmp) date with confirmatory first or second trimester ultrasound (us) scan, or uncertain lmp with second trimester ultrasound, intrauterine insemination (iui), or embryo transfer, or certain or uncertain lmp with fundal height and no confirmatory first or second trimester scan; second, hc 2 sd below mean or less than 3 percentile according to fetal us scan using appropriate standardized reference charts according to ga and gender for the population (e.g., who growth reference charts if ga greater than or equal to 37 weeks and intergrowth-21st reference charts for ga 24-36 weeks); third, hc at birth or autopsy is in the normal range using appropriate standardized reference charts according to ga and gender for the population, which means that this is not a case of prenatally diagnosed congenital microcephaly.

  • GAIA Postnatally Diagnosed Congenital Microcephaly Level of Diagnostic Certainty|Global Alignment of Immunization safety Assessment in pregnancy Postnatally Diagnosed Congenital Microcephaly Level of Diagnostic Certainty|Postnatally Diagnosed Congenital Microcephaly Level of Diagnostic Certainty

    a classification of maternal and fetal outcomes relating to diagnosing congenital microcephaly postnatally, developed by the global alignment of immunization safety assessment in pregnancy, based on the extent to which the diagnosis has been confirmed.

  • GAIA Prenatally Diagnosed Congenital Microcephaly Level of Diagnostic Certainty|Global Alignment of Immunization safety Assessment in pregnancy Prenatally Diagnosed Congenital Microcephaly Level of Diagnostic Certainty|Prenatally Diagnosed Congenital Microcephaly Level of Diagnostic Certainty

    a classification of maternal and fetal outcomes relating to diagnosing congenital microcephaly prenatally, developed by the global alignment of immunization safety assessment in pregnancy, based on the extent to which the diagnosis has been confirmed.

  • Microcornea

    a congenital abnormality characterized by an abnormally small cornea. the horizontal corneal diameter is less than 10mm or less than 9mm in newborns. it is associated with an increased risk of glaucoma.

  • Hydranencephaly

    a rare congenital brain disorder in which the cerebral hemispheres are absent and replaced by sacs that contain cerebrospinal fluid. signs and symptoms include irritability, increased muscle tone, seizures, and hydrocephalus. the prognosis is poor.

  • Psoriasiform Dermatitis

    a chronic, sporadic, acquired pruritic non-infectious skin condition characterized by one or more well defined inflamed (pink or red) patches or plaques of varying size.

  • Permanent Neonatal Diabetes Mellitus

    hyperglycemia in the first month of life due to a genetically determined defect in the structure, secretion and/or function of insulin that does not resolve spontaneously.

  • Cortical Blindness

    visual impairment due to visual cortex dysfunction.

  • Feingold Syndrome

    a rare autosomal dominant syndrome caused by mutations in the mycn oncogene. it is characterized by microcephaly, limb abnormalities, esophageal and/or duodenal atresia.

  • Congenital Kyphosis

    an abnormally increased curvature of the thoracic portion of the spine that is present at the time of birth.

  • Homeostatic Model Assessment of Insulin Resistance

    an assessment of beta-cell function and insulin resistance based on fasting blood glucose and insulin concentrations.

  • Hyperandrogenism, Insulin Resistance, Acanthosis Nigricans Syndrome|HAIR-AN Syndrome

    a condition characterized by hyperandrogenism, insulin resistance, and acanthosis nigricans, typically associated with obesity in teenage girls. it is considered to be a subtype of polycystic ovarian syndrome, but may occur in male individuals. etiology is unclear, but some cases may be associated with mutations affecting the tyrosine kinase domain of the insulin receptor.

  • Insulin Receptor Mutation - Associated Insulin Resistance Syndromes

    insulin resistance caused by inactivating mutation(s) in the insr gene encoding the insulin receptor.

  • Insulin Resistance

    decreased sensitivity to circulating insulin which may result in acanthosis nigicrans, elevated insulin level or hyperglycemia.

  • Insulin Resistance Measurement|INSULINR|Insulin Resistance|Insulin Resistance

    the determination of the insulin resistance (cells inability to respond to insulin) in a biological specimen.

  • Insulin Resistance Syndrome

    a cluster of closely related metabolic abnormalities associated with insulin resistance that confer an increased risk of the development of type 2 diabetes and cardiovascular disease. these abnormalities may include obesity, high blood pressure, abnormal cholesterol levels, proteinuria, and/or polycystic ovary syndrome.

  • Insulin Resistant Diabetes Mellitus with Acanthosis Nigricans and Hyperandrogenism|Type A Insulin Resistance Syndrome

    a syndrome of insulin resistance caused by mutation(s) in the insr gene, encoding the insulin receptor. this condition is characterized by a clinical triad of hyperinsulinemia, acanthosis nigricans, and hyperandrogenism without lipodystrophy. this is the least severe of a spectrum of disorders; the other two conditions are rabson-mendenhall syndrome and donohoe syndrome.

  • Obesity-Associated Insulin Resistance

    insulin resistance associated with obesity, which may be attributed in part to impaired insulin signaling in target tissues, or impaired insulin-stimulated glucose transport due to reduced expression of the glucose transporter protein 4.

  • Grade 1 Hypernatremia, CTCAE|Grade 1 Hypernatremia

    >uln-150 mmol/l

  • Grade 2 Hypernatremia, CTCAE|Grade 2 Hypernatremia

    >150-155 mmol/l; intervention initiated

  • Grade 3 Hypernatremia, CTCAE|Grade 3 Hypernatremia

    >155-160 mmol/l; hospitalization indicated

  • Grade 4 Hypernatremia, CTCAE|Grade 4 Hypernatremia

    >160 mmol/l; life-threatening consequences

  • Grade 5 Hypernatremia, CTCAE|Grade 5 Hypernatremia

    death

  • Hypernatremia

    higher than normal levels of sodium in the circulating blood.

  • Hypernatremia, CTCAE|Hypernatremia|Hypernatremia

    a disorder characterized by laboratory test results that indicate an elevation in the concentration of sodium in the blood.

  • GAIA Level 1 Neonatal Encephalopathy|Global Alignment of Immunization safety Assessment in pregnancy Level 1 Neonatal Encephalopathy|Level 1 Neonatal Encephalopathy

    gaia level 1 neonatal encephalopathy is defined by three criteria: first, a newborn infant (1-28 days of life) born at or beyond 35 weeks of gestation; second, an abnormal level of alertness or seizures; third, difficulty with initiating and maintaining respiration; fourth, depression of muscle tone.

  • GAIA Level 2 Neonatal Encephalopathy|Global Alignment of Immunization safety Assessment in pregnancy Level 2 Neonatal Encephalopathy|Level 2 Neonatal Encephalopathy

    gaia level 2 neonatal encephalopathy is defined by three criteria: first, a newborn infant (1 to 28 days of life) born at or beyond 35 weeks of gestation; second, an abnormal level of alertness or seizures; third, either difficulty with initiating and maintaining respiration or depression of muscle tone.

  • GAIA Level 3 Neonatal Encephalopathy|Global Alignment of Immunization safety Assessment in pregnancy Level 3 Neonatal Encephalopathy|Level 3 Neonatal Encephalopathy

    gaia level 3 neonatal encephalopathy is defined by three criteria: first, a newborn infant (1-28 days of life) born at or beyond 35 weeks of gestation; second, an abnormal level of alertness or seizures; third, none of the following: a) difficulty with initiating or maintaining respiration; b) depression of muscle tone.

  • GAIA Neonatal Encephalopathy Level of Diagnostic Certainty Terminology|Global Alignment of Immunization safety Assessment in pregnancy Neonatal Encephalopathy Level of Diagnostic Certainty

    a subset of terminology related to neonatal encephalopathy, developed by the global alignment of immunization safety assessment in pregnancy consortium to aid in monitoring and improving fetal and maternal outcomes.

  • GAIA Neonatal Encephalopathy Level of Diagnostic Certainty|Global Alignment of Immunization safety Assessment in pregnancy Neonatal Encephalopathy Level of Diagnostic Certainty|Neonatal Encephalopathy Level of Diagnostic Certainty

    a classification of maternal and fetal outcomes relating to neonatal encephalopathy, developed by the global alignment of immunization safety assessment in pregnancy, based on the extent to which the diagnosis has been confirmed.

  • Neonatal Encephalopathy

    abnormal functioning of the central nervous system in the newborn period that may be due to a variety of etiologies including hypoxia/ischemia, metabolic disturbance, or infection.

  • Severe Neonatal Encephalopathy Due to MECP2 Mutations

    an x-linked recessive condition caused by mutation(s) in the mecp2 gene, encoding methyl-cpg-binding protein 2. it is characterized by severe neonatal encephalopathy.

  • Multinucleated Neurons, Anhydramnios, Renal Dysplasia, Cerebellar Hypoplasia And Hydranencephaly|MARCH

    a lethal autosomal recessive condition caused by mutation(s) in the cep55 gene, encoding centrosomal protein of 55 kda. it is characterized by renal dysplasia, anhydramnios, hydrancephaly, cerebellar hypoplasia, and multinucleated neurons in remaining brain tissue.

Patient EducationClinical

Brain Malformations

Most brain malformations begin long before a baby is born. Something damages the developing nervous system or causes it to develop abnormally. Sometimes it's a genetic problem. In other cases, exposure to certain medicines, infections, or radiation during pregnancy interferes with brain development.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Q02 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
742.1 Microcephalus
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Q02Overview

Is Q02 (Microcephaly) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report microcephaly on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is Q02 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for microcephaly on inpatient claims.

What is the ICD-9 equivalent of Q02?

Under the General Equivalence Mappings, microcephaly converts to ICD-9-CM 742.1 (microcephalus). The mapping is a direct match.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.