Nearly 300 pregnant women in the US have tested positive for Zika virus, according to the latest figures from the Centers for Disease Control and Prevention (CDC).
In the US, 157 pregnant women have tested positive for the disease and 122 have tested positive in US territories.
Until now, the agency had not reported the number of women infected by the diseases in the US and its territories.
The virus is spread through mosquitoes and sexual contact.
It can cause microcephaly, a birth defect, marked by a small head size and can lead to developmental problems in infants.
Symptoms of Zika virus include mild fever, conjunctivitis, headache, joint pain and rashes.
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Death from the disease is rare and there is no vaccine or drug treatment available.
In Los Angeles, officials are taking prevention measures against Zika after health officials warned that outbreaks could be expected in Southern California.
The outbreak began nearly a year ago in Brazil.
The World Health Organization has said Zika virus could spread to Europe this summer.
“Everything we know about this virus seems to be scarier than we initially thought,” Dr Anne Schuchat of the CDC said in April.
Earlier this year, US President Barack Obama asked the US Congress for $1.9bn (£1.25bn) in emergency funding to combat the virus.
In the meantime it has been using money totalling $589m left over from the Ebola virus fund.