Scientists found that 13 infants in Brazil who were exposed to the mosquito - borne
virus during gestation had normal head size as newborns, but subsequently experienced slower head growth.
Women were also excluded from the analysis if the first prenatal visit was after 20 weeks
gestation or if the mother self - reported diabetes, hypertension, known human immunodeficiency
virus status, or use of illicit drugs or cigarettes
during pregnancy.