Mexico has launched a radio and television ad campaign to encourage pregnant women to take measures to avoid getting Zika.
Mexico has only 37 confirmed cases, none of them among pregnant women.
But the Health Department says pregnant women should take special care after babies were born in Brazil with extremely small heads, possibly related to their mothers being infected with the Zika virus. The broadcast ads urge pregnant women to wear long-sleeved clothing, use mosquito repellant and keep windows and doors closed.
The ads are scheduled to run at least through March, and tell women the disease "could seriously affect your pregnancy."
Latin American health ministers meeting in Uruguay are focusing on why Zika has been linked to birth defects in Brazil but not in other countries where the virus has been detected.
Colombian Health Minister Alejandro Gaviria told The Associated Press Wednesday that researchers need to look at what may be fueling the differences in manifestations.
He gave the example of Colombia, where 20,000 cases of Zika have been confirmed but not a single case of microcephaly, or smaller than normal head size in infants.
Brazilian officials have recorded 3,670 suspected cases of microcephaly since October. Brazil's Heath Ministry says the rare brain defect in babies has been confirmed in 404 of those cases.
Infants with microcephaly have smaller than normal heads and their brains do not develop properly.