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Body + BrainBody & Brain

Up to 29% of Zika-Affected Pregnancies Result in Brain Damage to the Baby

ByAllison EckNOVA NextNOVA Next

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Rates of Zika infection in Brazil have begun to decline, but the danger to newborns is just as imminent—if not more so.

Brazilian doctors are now claiming that neurological abnormalities could affect the babies of up to one-fifth of Zika-infected pregnant women.

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A separate study in the New England Journal of Medicine reported that figure at 29% (12 out of 72 fetuses). Though the statistics are fuzzy, the ramifications are hardly objectionable: Zika is associated with brain damage in the womb—and it’s happening more frequently than we once thought.

Scientists suspect that exposure to Zika in utero could lead to microcephaly, a birth defect in which the baby’s head size is below average. But much of what doctors are finding in the fetuses of Zika-affected women does not so obviously look like microcephaly—instead, a broad range of brain deficiencies are manifesting themselves.

Microcephaly-2
Zika is suspected to have a direct link to microcephaly, shown here on the right (compare to the normal-sized brain, on the left).

Here’s Wyre Davis, interviewing Renato Sa, a senior obstetrician in Rio de Janeiro, for BBC News:

“There are cerebral calcifications, an increase in the number of dilation of cerebral ventricles and the destruction or malformation of the posterior part of the brain,” he says.

In my notebook he makes a list of the conditions that they are now witnessing with increasing regularity; ventriculomegaly, damage of the posterior fossa, craniocynostosis and cerebral calcification.

He says that an added concern is that often there is no obvious sign or symptom of the neurological damage until later observations of the child’s development, “perhaps convulsions or other tell-tale signs.”

Using stem cell technology, one team of experts has found that the presence of Zika in the womb reduces growth of the cerebral cortex, the outer layer of the brain that plays a fundamental role in consciousness. In the carrier, Zika may also contribute to mental illness . Just how Zika goes about destroying neurons is not known, but the risk to pregnant women is abundantly clear.