What is Zika Virus and Pregnancy?

Zika virus is spread mainly through the bite of infected mosquitoes in certain tropical and subtropical regions, and can also be passed on through sex. Infection during pregnancy is a particular concern because it can cause serious birth defects, including microcephaly (an unusually small head, associated with brain development problems) and other neurological issues, with the highest risk linked to infection in the first and second trimesters.

Many people infected with Zika have mild symptoms — such as fever, rash, joint pain, and red eyes — or no symptoms at all, which is why avoiding exposure through travel precautions is the main way to reduce risk during pregnancy.