Birth defects seen in 6 per cent of US pregnancies with Zika

A US study of pregnant women with Zika finds that 6 per cent of the pregnancies resulted in birth defects. The rate was nearly twice as high for women infected early in pregnancy.

The authors say the US findings fit with research from other countries.

All 442 women were infected outside the United States, or had sex with someone who got Zika in an outbreak area. Zika is spread primarily by mosquitoes and has mostly affected the Caribbean and Latin America.

Birth defects were seen in 21 babies and in five miscarriages, stillbirths or abortions.

Previous research suggests that a Zika infection early in pregnancy results in severe brain-related birth defects in roughly 1 per cent to 15 per cent.

The study was published by the Journal of the American Medical Association.