(HealthDay News) — Zika’s ability to damage the infant brain may be even more far-reaching and insidious than previously thought, two new studies suggest.
The first report was published online Dec. 15 in the Journal of the American Medical Association. Analyzing data from the U.S. Zika Pregnancy Registry, Margaret A. Honein, Ph.D., from the U.S. Centers for Disease Control and Prevention in Atlanta, and colleagues found that among 442 women possibly infected with Zika, 6 percent had infants with one or more birth defects related to Zika. Among women infected in the first trimester, 11 percent had fetuses or infants with birth defects. The 18 infants who developed microcephaly accounted for 4 percent of the infants with birth defects.
In the second study, published online Dec. 15 in the New England Journal of Medicine, Patrcia Brasil, M.D., Ph.D., from the Oswaldo Cruz Foundation in Rio de Janeiro, and colleagues found that among Brazilian women, adverse pregnancy outcomes occurred in 46.4 percent of 125 pregnancies of women infected with Zika. The risks of birth defects occurred at all stages of infection during pregnancy: 55 percent in the first trimester; 52 percent in the second trimester; and 29 percent in the third trimester. Among 117 live births among women infected with Zika, 42 percent of infants were found to have abnormalities on clinical examination, imaging, or both.
“Despite mild clinical symptoms in the mother, Zika virus infection during pregnancy is deleterious to the fetus and is associated with fetal death, fetal growth restriction, and a spectrum of central nervous system abnormalities,” Brasil and colleagues write.