Acute Zika virus infection during pregnancy has been associated with fetal death and fetal brain defects, but what is the extent of abnormal CNS findings in affected infants after birth? A recent study published in the New England Journal of Medicine explored this question.

This prospective cohort study conducted in Rio De Janeiro, Brazil sought to compare infant outcomes for mothers acutely infected with Zika virus at any period of gestation versus those for infants born to uninfected mothers. The study found that 42% of live births in Zika infected pregnancies had evidence of CNS abnormalities (such as microcephaly, intracranial classifications, cerebral malformations, ophthalmologic lesions) on clinical exam or brain imaging. This was significantly greater than the rate of 5% for such abnormalities observed in their uninfected cohorts. These findings lead the investigators to conclude that despite mild clinical symptoms in the mother, Zika infection during pregnancy is deleterious to the fetus and is associated with fetal death, fetal growth restriction, and a spectrum of central nervous system abnormalities.

Reference(s): Brasil, P., Pereira, J. P. J., Moreira, M. E., Ribeiro Nogueira, R. M., Damasceno, L., Wakimoto, M., . . . Nielsen-Saines, K. (2016). Zika Virus Infection in Pregnant Women in Rio de Janeiro. New England Journal of Medicine, 375(24), 2321-2334.