MIAMI • About 6 per cent of babies born in the United States to mothers infected with the mosquito- borne Zika virus while pregnant had birth defects, US researchers said last Thursday.
The report by the US Centres for Disease Control and Prevention (CDC) was published in the Journal Of The American Medical Association.
"CDC scientists used preliminary data from the US Zika Pregnancy Registry to estimate that 6 per cent of completed pregnancies follow- ing Zika virus infection were affected by one or more birth defects potentially related to Zika virus infection during pregnancy," said the report.
A total of 442 women with possible Zika infection had given birth by Sept 22, and 26 of the pregnancies, or six per cent, resulted in birth defects that may be linked to Zika. It can cause babies to be born with malformed brains and unusually small heads, a condition known as microcephaly.
The rate of defects was higher - 11 per cent - among women infected with Zika in the first trimester of their pregnancies.
In four out of five cases, Zika infection causes no symptoms at all. Those who do report symptoms may have a rash, headache or body pain. Eighteen infants were diagnosed with microcephaly, representing 4 per cent of the completed pregnancies.
The report said its estimates were preliminary and could rise, as recent research showed that some Zika babies appeared normal at birth but went on to develop microcephaly in their first year of life.