METHODS
The Natural History of ZIKA Virus Infection in Gestation (NATZIG) project is a prospective population-based cohort study undertaken in the entire Ribeirão Preto region (population 1,720,469)16, in northeastern São Paulo state, Brazil. In this paper, we enrolled symptomatic ZIKV-infected pregnant women and -exposed infants during the 2015-2016 ZIKV outbreak. All study procedures received ethical approval (Processes #7404/2016, #5914/2017), and written informed consent was obtained from all participants.