Study shows evidence of Zika virus' risk to pregnant women

The researchers also found that the virus can affect pregnancy at any stage.

AP Photo/Andrew Penner

Scientists have yet to prove without a doubt that the mosquito-borne Zika virus causes microcephaly. A big study involving 5,000 women being conducted right now will help determine that, but the results won't be out until mid-year. This much smaller study by UCLA researchers, however, strengthens the link between the virus and various birth defects -- not just microcephaly -- as well as fetal death. In addition, the researchers found that Zika can affect pregnancy at any stage and trimester. The study's senior author, Dr. Karin Nielsen, said they saw problems with pregnant women eight weeks, 22 weeks, 25 weeks and even 35 weeks along.

The team studied 88 pregnant women who went to a clinic at the Oswaldo Cruz Foundation in Rio de Janeiro with the intention of being tested for the virus. Out of the 88 individuals, 72 tested positive for Zika; 42 of them, as well as the 16 who tested negative, agreed to undergo further tests and ultrasounds. A total of 12 subjects among the 42 infected women had problematic ultrasound results, and two of them ended up losing their babies in their third trimester.

Of the six live births overall, two babies were too small, while one was born with severe microcephaly. One of the small babies and the infant with microcephaly had lesions in their eyes indicating blindness. Another had to be delivered via C-section, because the mother's uterus had no amniotic fluid. Two of the mothers who had normal ultrasound results delivered healthy babies.

Nielsen says their study and others like it could help eliminate theories that the pesticides used against mosquitoes (and not the virus itself) are the culprit. Those theories led people to protest against their use, which Nielsen believes is a "really bad idea," explaining that "you want to enhance vector control to prevent infection and not abandon that approach during an epidemic." Besides UCLA's research, another one conducted by Johns Hopkins, Florida State and Emory universities have shown through lab testing that the virus kills tissues that form the brain and the nervous system.