There are growing concerns among expectant mothers, who have recently travelled to countries affected by the Zika virus.

There are concerns that they might have been exposed to the mosquito-borne infection. The dangerous Zika virus is already linked to a rash of microcephaly that causes birth defects in babies, who are born with unusually small heads. The healthcare workers in Brazil, Colombia and El Salvador have advised women in those countries to avoid the risk by postponing pregnancies. The researchers are yet to determine how the virus may affect infants.

The new guidelines in the US only permit blood test for ant women with symptoms of infection but a majority of them do not show symptoms and this leaves them unaware about the infection. The US Centers for Disease Control and Prevention has also advised pregnant women not to travel to countries with Zika virus outbreak. It added the warning to 22 destinations, most of which are in Latin America and the Caribbean nations.

The American College of Obstetricians and Gynecologists said that hundreds of women have called for advise after travelling to the affected region. The US Centers for Disease Control and Prevention is working to determine how many pregnant women may have traveled to affected regions in the past several months and has advised doctors to administer blood tests only for pregnant women with symptoms.