Infants exposed to Zika virus in the womb showed neurodevelopmental delays as toddlers despite having "normal" brain imaging and head circumference at birth—underscoring the importance of long-term neurodevelopmental follow-up for Zika-exposed infants, according to a study published online in JAMA Pediatrics.
"These infants had no evidence of Zika deficits or microcephaly at birth. Neurodevelopmental deficits, including declines in mobility and social cognition, emerged in their first year of life even as their head circumference remained normal," says study first author Sarah B. Mulkey, MD, PhD, a fetal/neonatal neurologist at Children's National Hospital in Washington, D.C. "About one-third of these newborns who underwent postnatal head ultrasound had nonspecific imaging results, which we believe are the first published results finding a link between subtle brain injuries and impaired neuromotor development in Zika-exposed children."
A multi-institutional research group led by Children's National enrolled pregnant women in Atlántico Department, which hugs the Caribbean coast of Colombia, who had been exposed to Zika. Researchers performed a series of fetal magnetic resonance images and ultrasounds as their pregnancies progressed.
Even though their mothers had laboratory-confirmed Zika infections, 77 out of 82 of their offspring were born with no sign of congenital Zika syndrome, a constellation of birth defects that includes severe brain abnormalities, eye problems, and congenital contractures, and 70 underwent additional testing of neurodevelopment during infancy. These apparently normal newborns were born between August 1, 2016, and November 30, 2017, at the height of the Zika epidemic, and had normal head circumference.
When they were 4 to 8 months or 9 to 18 months of age, the infants' neurodevelopment was evaluated using the Warner Initial Developmental Evaluation of Adaptive and Functional Skills (a 50-item test of such skills as self-care, mobility, communication, and social cognition) and the Alberta Infant Motor Scale (a motor examination of infants in prone, supine, sitting, and standing positions). Some infants were assessed during each time point.
"Normally, neurodevelopment in infants and toddlers continues for years, building a sturdy neural network that they later use to carry out complex neurologic and cognitive functions as children enter school," Dr. Mulkey adds. "Our findings underscore the recommendations by the Centers for Disease Control and Prevention that all infants exposed to Zika in the womb undergo long-term follow-up, providing an opportunity to intervene earlier."
Source: Children's National Hospital, January 6, 2020