A baby with microcephaly (left) compared to a baby with a typical-sized head (right)WIKIMEDIA, CDCAn analysis published this week (May 25) in The New England Journal of Medicine has quantified the estimated risk of microcephaly in the developing fetuses of pregnant women infected with Zika virus. Using data from the Zika-hit state of Bahia in Brazil, researchers estimated the risk of microcephaly when mothers were infected during the first trimester of pregnancy to be between 1 percent and 13 percent.
“It is an appreciable risk,” study coauthor Michael Johansson of the US Centers for Disease Control and Prevention (CDC) told The Washington Post. “We need to do whatever we can to help women avoid Zika virus infections during pregnancy.”
In April, the CDC declared that sufficient evidence had accumulated to support a causal link between Zika virus infection and microcephaly and other birth defects; a study published earlier this month provided further support for the link, showing that the virus could cause microcephaly and other defects in developing mouse embryos. However, the present study is one of the first to provide a quantitative estimate of an infant’s risk of microcephaly following maternal infection.
This estimate is the result of an analysis of Zika virus infection ...