The Philippines confirmed its first reported case of a pregnant woman infected with the Zika virus on Monday.
The Health Secretary Paulyn Ubial said 12 Zika virus cases have been detected across the nation in September. The list also includes a 22-year-old woman from the central island of Cebu who is 19 weeks' pregnant with her first child.
"Initial ultrasound did not detect any foetal abnormalities. She will be monitored regularly during the entire period of the pregnancy," the health department said.
The department said eight out of those 12 cases were female and ranged in the age group from 9 to 55.
It also added that none of those infected patients had travelled a month before testing positive and all had since recovered.
Authorities have warned people to be vigilant and avoid mosquitoes.
Zika is a mosquito-borne virus that was first identified in Uganda in 1947. It can be passed from a pregnant woman to her unborn baby.
The virus can cause birth defects and can also result in microcephaly in which the baby's head is smaller than expected.
The government has dispatched special teams to all the affected areas to investigate where the infection came from and recommend measures to deal with the virus.
Ms Ubial urged the public to detect and destroy mosquito breeding places. He also asked the members of the public to use insect repellent and wear condoms during sex as the virus can be spread by the bite of a mosquito or via sexual contact.
The World Health Organisation said people infected with Zika can have symptoms including mild fever, skin rash, conjunctivitis, muscle and joint pain, malaise or headache. These symptoms of Zika normally last for two to seven days.
Meanwhile, the scientists warned that the world should prepare for a "global epidemic" of microcephaly. There is no vaccine for Zika at present.