Since the onset of the Zika outbreak, health officials said a large number of newborns in Brazil are suffering a condition that is characterized by an abnormally small head.

Any pregnant woman who has traveled to a Zika-affected area during pregnancy should be evaluated and tested, regardless of symptoms; pregnant women whose male partners have traveled to an area with Zika need to be concerned about sexual transmission of the Zika virus and the male should use condoms every time or not have sex during the pregnancy.

Couples who are trying to get pregnant should postpone travel to all Zika-affected areas.

Women who have traveled to one of these areas and have been diagnosed with Zika or are showing symptoms should wait at least two months before conceiving.

Both men and women are encouraged to use condoms or not have sex for at least eight weeks after returning from a Zika-affected country even if they do not develop symptoms consistent with the virus. Up to 80% of people who have Zika do not have symptoms.

While there have been 346 travel-related Zika cases in the U.S., the CDC said there have been no locally-acquired Zika cases. Of the 346 reported, 32 were pregnant women, seven were sexually transmitted and one had Guillain-Barré syndrome.