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

This retrospective cohort study included 7,870 pregnant women (2,269 with confirmed Zika virus (ZIKV) infection and 5,601 without Zika infection) and their concepts. We obtained data from different databases in the state of Rio de Janeiro, Brazil. We used a propensity score model to control for confounding factors and stratify between the trimesters of pregnancy. Of the 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). The multivariable analysis evidenced an odds ratio of 2.46 (95% CI 1.30-4.64), 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 common findings among ZIKV+ cases were intracranial calcifications, ventriculomegaly, posterior fossa malformations, reduced brain volume, corpus callosum malformations, cortex dysplasia, lissencephaly, and pachygyria. 55.5% of the ophthalmologic exams were abnormal, and anomalies % of brainstem auditory evoked potentials were reported in 33.3%.