Mexico has confirmed six pregnant women are infected with the Zika virus, bringing the total number of cases in the country to 80, the government said.
They are believed to be the first confirmed cases of Zika in pregnant women in Mexico.
More than half of the total cases of Zika and four of the infected women were detected in the poor southern state of Chiapas, a report from the health ministry said late on Monday.
Pope Francis visited Chiapas on Monday, drawing crowds of thousands.
One of the other infected pregnant women is from the southwestern state of Oaxaca, while another is from the eastern state of Veracruz.