Zika virus during pregnancy: From maternal exposure to congenital Zika virus syndrome.

Zika virus (ZIKV), a vector-borne virus similar to dengue virus, was responsible for a global epidemic between 2013 and 2017 and has emerged as a new agent responsible for severe fetopathies. We present a review to describe the risks and complications of maternal and subsequent fetal infection by ZIKV. The risk of ZIKV infection during pregnancy depends on the incidence of the disease, which is highly variable in different affected geographic areas (less than 1% to 75%). Among infected pregnant women, the risk of any adverse fetal/neonatal outcome was estimated at 5% to 42%, with 1% to 4% of fetal loss and 4% to 9% of suspected congenital Zika syndrome (CZS). The estimated rate of maternal-fetal transmission ranges between 7% and 26%, depending on the methodology of the study. Findings associated with CZS are microcephaly (33%-64%), ventriculomegaly (63%-92%), calcifications (71%-92%), malformations of cortical development (79%-82%), anomalies of the corpus callosum (71%-100%) and of the posterior fossa (21%-82%), arthrogryposis (10%-25%), eye abnormalities (25%), and extra-neurologic signs such as intra uterine growth restriction (14%), placentomegaly, transient hepatitis, mild anemia. Infants who present with CZS at birth suffer from motor abnormalities (77%-100%), epilepsy (9%-54%), hearing loss, and neurologic impairments. Prenatal ultrasound with advanced neurosonography and appropriate virological follow-up represent the state-of-the art approach to adequately monitor at-risk pregnancies, in order to diagnose early signs of CZS and to inform parents about the neonatal prognosis.