Women have up to a 13 percent chance of their babies being born with the birth defect microcephaly from the Zika virus, according to a new study.
The study published in the New England Journal of Medicine Wednesday estimated the risk of getting microcephaly from Zika ranged from just under 1 percent to 13 percent. The study also found that the most vulnerable time to get Zika is in the first trimester of pregnancy, as the risk of the birth defect falls off in the second and third trimesters.
The study offers new information on the risks facing women from the Zika virus, which is spread primarily by mosquito bites.
It also comes as the House and Senate fight over how much money to spend to fight the virus.
The study looked at the rate of microcephaly cases in French Polynesia, which had a massive Zika outbreak in 2013. It considered the different infection rates and possible overreporting of the Zika virus.
After taking those factors into account, the researchers estimated the risk for someone in the first trimester to range between 0.88-13.2 percent.
Researchers noted there are a slew of caveats and limitations with any estimates of microcephaly risk compared with Zika infection.
“First, available data are very limited, especially in recently affected areas such as Bahia [a state in Brazil], where infection rates are unknown and microcephaly cases are still being reported and evaluated,” the study said. Brazil is one of the countries hardest hit by the Zika virus.
The researchers also had an uncertain baseline of microcephaly cases, going with a wide rate of two-12 cases per 10,000 births.
So far, mosquitoes are not spreading the virus within the continental U.S. Health officials have found 544 cases in the U.S. as of May 18, but almost all are from people who recently traveled to a country where the virus is spreading through mosquitoes.
The new findings come as Democrats and some Republicans argue about getting a final Zika funding deal through Congress. The House and Senate have passed competing Zika funding packages, with the House opting for $622 million in offset funding and the Senate $1.1 billion in new funding.
No conference has been announced to reconcile the difference, and Congress is about to leave for its Memorial Day recess. Lawmakers return June 7.
