Prevalence of Zika-Related Birth Defects Greater Than Thought

Share this content:
Deficits include neurodevelopmental and physical abnormalities.
Deficits include neurodevelopmental and physical abnormalities.

HealthDay News -- New research suggests that Zika's ability to damage the infant brain may be even more far-reaching and insidious than previously thought.

The first report was published online December 13 in the Journal of the American Medical Association.1 Analyzing data from the US Zika Pregnancy Registry, Margaret A. Honein, PhD, from the US Centers for Disease Control and Prevention in Atlanta, and colleagues found that among 442 women possibly infected with Zika, 6% had infants with 1 or more birth defects related to Zika. Among women infected in the first trimester, 11% had fetuses or infants with birth defects. The 18 infants who developed microcephaly accounted for 4% of the infants with birth defects.

In the second study, published online December 15 in the New England Journal of Medicine,2 Patrcia Brasil, MD, PhD, from the Oswaldo Cruz Foundation in Rio de Janeiro, and colleagues found that among Brazilian women, adverse pregnancy outcomes occurred in 46.4% of 125 pregnancies of women infected with Zika. The risks of birth defects occurred at all stages of infection during pregnancy: 55% in the first trimester; 52% in the second trimester; and 29% in the third trimester. Among 117 live births among women infected with Zika, 42% 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," Dr Brasil and colleagues wrote.


  1. Honein MA, Dawson AL, Petersen EE, et al; for the US Zika Pregnancy Registry Collaboration. Birth defects among fetuses and infants of US women with evidence of possible zika virus infection during pregnancy. JAMA. 2016 Dec 13; doi:10.1001/jama.2016.19006.
  2. Brasil P, Pereira JP, Raja gabaglia C, et al. Zika virus infection in pregnant women in Rio de Janeiro - preliminary report. N Engl J Med. 2016; doi:10.1056/NEJMoa1602412.
You must be a registered member of Neurology Advisor to post a comment.

Sign Up for Free e-newsletters

CME Focus