TABLE 3.

Congenital anomalies potentially related to maternal ZIKV infection.

Brain Abnormalities • Congenital microcephaly: HC < 3rd centile for gestational age and sex • Intracranial calcifications • Cerebral atrophy • Abnormal cortical formation (lissencephaly, polymicrogyria, pachygyria, schizencephaly, and gray matter heterotopia) • Corpus callosum abnormalities • Cerebellar abnormalities • Porencephaly • Hydranencephaly • Ventriculomegaly* or hydrocephaly* • Fetal brain disruption sequence (severe microcephaly, collapsed skull, overlapping sutures, scalp redundancy) • Other major brain abnormalities (thalamus, hypothalamus, pituitary, basal ganglia, or brainstem)

Neural Tube Defects and Other Early Brain Malformations** • Anencephaly or acrania • Encephalocele • Spina bifida without anencephaly • Holoprosencephaly or arhinencephaly

Eye Abnormalities • Microphthalmia or anopthalmia • Coloboma • Congenital cataract • Intraocular calcifications • Chorioretinal anomalies (e.g., atrophy, scarring, macular pallor, retinal hemorrhage and gross pigmentary changes excluding retinopathy of prematurity) • Optic nerve atrophy, pallor and other optic nerve abnormalities

Consequences of Central Nervous System Dysfunction • Congenital contractures (e.g., arthrogryposis, club foot, congenital hip dysplasia) with associated brain abnormalities • Congenital sensorineural hearing loss documented by postnatal testing

Table adapted from the US Centers for Disease Control standard case definition for birth defects potentially associated with ZIKV infection (World Health Organization (WHO)., 2018a). *Excludes isolated mild ventriculomegaly without other brain abnormalities or hydrocephalus due to hemorrhage. **Evidence for a link between ZIKV infections and neural tube defects is weaker than for other listed anomalies.