NEW YORK (AP) — U.S. health officials on Friday said men who have been to a Zika outbreak region should use condoms if they have sex with a pregnant woman — for the entire duration of the pregnancy.

The guidance also said the men might consider abstaining or using condoms even during sex with a woman who isn’t pregnant.

The Centers for Disease Control and Prevention stressed that the Zika virus is still mainly spread by mosquitoes. In most people, it causes mild or no symptoms. But it has become a concern because of a possible link with a birth defect in Brazil.

The CDC has recommended that pregnant women postpone trips to countries with Zika outbreaks, mostly in Latin America and the Caribbean. All travelers are advised to use insect repellent and take other steps to avoid mosquito bites.

The health agency also on Friday updated its guidelines for testing and monitoring pregnant women who have traveled to Zika areas. In the U.S., there have been about 50 cases of travelers diagnosed with the virus, including three pregnant women.

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