As researchers begin to understand more about the Zika virus, the CDC is updating its recommendations for the public based on new information. On Sept. 30, the agency changed its guidelines to recommend couples wait at least six months from the last possible exposure to Zika before trying to become pregnant.

Men who could have been exposed to the virus, even without symptoms, are included in these new cautionary rules. CDC officials said the virus remains in some bodily fluids, such as semen, for longer than originally thought. The CDC had previously recommended couples wait to become pregnant for only eight weeks after a man’s most recent exposure. The man could sexually transmit the disease to his partner who could then pass along the virus and its associated complications to any resultant fetuses.

Women who have been exposed to Zika are still advised to wait eight weeks after the last possible exposure before getting pregnant to be sure the virus has left their system and avoid potential birth defects, including microcephaly, that could come with an infection during pregnancy.

As always, the CDC advised men and women who are pregnant (or whose partners are pregnant or are trying to get pregnant) to talk with their doctors about the risks of contracting Zika where they live or where they might travel. And even women who are not necessarily trying to become pregnant should talk to their physicians about the dangers of Zika and pregnancy, the CDC said.