And in another case, a baby had to be "urgently delivered" from a woman with a later Zika infection, because the baby would have died otherwise, she said.
None of those three cases involved microcephaly or other problems with the central nervous system, but rather, these cases had other problems such as placenta or amniotic fluid abnormalities, she said. There "may be a high risk of fetal demise with infections in the last trimester," she said.
The finding that nearly 30 percent of Zika-infected women had an abnormality on their ultrasound is "worrisome," the researchers said. They note that the rate of fetal death in women with Zika was 4.8 percent, which is about twice the rate of fetal death among women infected with HIV living in the same area.
However, Adalja said that because the new study was small and in a single area, more studies are needed before researchers know the true rate of Zika-related pregnancy complications. In addition, there were 30 women in the study who were infected with Zika but did not have an ultrasound. It will be important for future studies to perform ultrasounds on all Zika-infected women in order to generalize the findings, Adalja said. [The 9 Deadliest Viruses on Earth]