Neonatal Microcephaly and Central Nervous System Abnormalities During the Zika Outbreak in Rio de Janeiro

This retrospective cohort study analyzed 7870 pregnant women, including 2269 with confirmed Zika virus (ZIKV) infection and 5601 without Zika infection, along with their fetuses and newborns. Data were sourced from multiple databases in the state of Rio de Janeiro, Brazil. A propensity score model was employed to control confounding factors and stratify outcomes by pregnancy trimester. Among ZIKV+ pregnant women, 49 cases of congenital microcephaly or congenital nervous system (CNS) abnormalities were identified (2.16%, or 193.9 cases in 10,000 live births), whereas 44 cases were identified among ZIKV- women (0.78%, or 71.4 cases in 10,000 live births). Multivariable analysis yielded an odds ratio of 2.46 (95% CI 1.30-4.64) overall, with 4.29 (95% CI 1.93-9.53) in the first trimester, 5.29 (95% CI 1.08-25.95) in the second trimester, and 0.68 (95% CI 0.21-2.14) in the third trimester. The most frequent findings among ZIKV+ cases included intracranial calcifications, ventriculomegaly, posterior fossa malformations, reduced brain volume, corpus callosum malformations, cortex dysplasia, lissencephaly, and pachygyria. Ophthalmologic abnormalities were detected in 55.5% of cases, and brainstem auditory evoked potential anomalies were reported in 33.3%. ZIKV infection can result in structural or functional anomalies. Given the absence of specific treatment for congenital Zika syndrome (CZS), clinical care should prioritize monitoring and managing neurological, motor, auditory, visual, and orthopedic disorders in all children with in utero ZIKV exposure, especially during the first and second trimesters of pregnancy.