A new report detailing the potential dangers
that Zika poses to an unborn child reveals
that the virus appears to be most harmful
when transmitted from a pregnant mother to her fetus during the first trimester of
The report, published Tuesday in the journal Radiology, found that transmission of Zika virus during the first trimester increases the likelihood of severe brain defects in the baby, including microcephaly.
“The first trimester is the time where
infection seems to be riskiest for the
pregnancy,” said study coauthor Dr. Deborah Levine, the director of Obstetric &
Gynecologic Ultrasound at Beth Israel
Deaconess Medical Center and a professor of radiology at Harvard Medical School in
Boston, according to a news release.
“From an imaging standpoint, the abnormalities in the brain are very severe when compared to other congenital infections.”
The researchers performed a retrospective
review of imaging and autopsy findings
associated with congenital Zika virus
infection found in the Instituto de Pesquisa in Campina Grande state Paraiba (IPESQ) in
Northeastern Brazil. Of the 438 pregnant
patients referred to IPESQ due to rash during pregnancy or suspected abnormalities, imaging exams found that 17 fetuses had confirmed Zika infections while 28 had presumed Zika infections.
Imaging exams included fetal MRI, postnatal brain CT, postnatal brain MRI and
longitudinal prenatal ultrasound.
In addition to microcephaly, a condition in
which a child is born with an extremely small head due to an underdeveloped brain, the virus has been linked with eye defects,
hearing impairment and stunted growth in
In the report, researchers discovered that fetuses exposed to Zika virus also suffered from a variety of brain abnormalities
including gray and white matter volume loss, brainstem abnormalities, calcifications and ventriculomegaly, a condition in which the ventricles are enlarged.
In a news release, the researchers noted that the brain abnormalities seen in confirmed and presumed Zika groups were very similar, and that nearly all of the babies in each group had ventriculomegaly.
While most fetuses had at least one exam indicating significantly small head circumference, three fetuses with severe ventriculomegaly registered normal head circumference. All of the babies exhibited reduced tissue volume in their brains, and all patients experienced varying abnormalities in cortical development.