Officials in the four countries of Latin America and the Caribbean have warned women not to get pregnant in the middle of their concerns about the disease that causes severe disability since birth.
Colombia, Ecuador, El Salvador and Jamaica recommend women to delay pregnancy until more is known about the Zika virus carried by mosquitoes.
This warning was issued after the outbreaks in Brazil.
Brazil said the number of babies born with the disease is suspected microcephaly - or abnormally small head - has reached nearly 4,000 since October.
Meanwhile, the health authorities in the United States also warned pregnant women not to travel to more than 20 countries in the Americas where Zika cases have been recorded.
The relationship between microcephaly and Zika still unconfirmed - but a small number of infants who died were found to have the virus in their brains, and there is no other explanation for the surge in cases of microcephaly.
The virus is not contagious and usually makes people feel the symptoms just like the flu.
Image copyrightAP
Image caption
baby being bathed in Brazil is suffering from microcephaly.
His mother Zika virus spread mosquitoes while pregnant.
The researchers suspect that the virus causes brain damage to the fetus in the womb.
Is it zika virus?
The virus is spread by the Aedes aegypti mosquito, which also cause dengue fever and yellow fever (yellow fever)
This virus was first discovered in Africa in the 1940s but is now spreading also in Latin America
Scientists say the more evidence connecting with microcephaly, which causes babies born with small heads
Although the Zika virus can cause fever and rash, most people do not get any symptoms, and not yet known cure
The only way to combat Zika is clearing stagnant water where mosquitoes breed, and to protect themselves from mosquito bites
