Prenatal ultrasound can identify most abnormalities in fetuses exposed to Zika virus during pregnancy, and neuroimaging after birth can detect infant exposure in cases that appeared normal on prenatal ultrasound, according to research published in JAMA Pediatrics.

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“Absence of prolonged maternal viremia did not have predictive associations with normal fetal or neonatal brain imaging,” Sarah B. Mulkey, MD, PhD, from the division of fetal and transitional medicine at Children’s National Health System, in Washington, and her colleagues wrote. “Postnatal imaging can detect changes not seen on fetal imaging, supporting the current CDC [Centers for Disease Control and Prevention] recommendation for postnatal cranial [ultrasound].”

Dr. Mulkey and her colleagues performed a prospective cohort analysis of 82 pregnant women from Colombia and the United States who had clinical evidence of probable exposure to the Zika virus through travel (U.S. cases, 2 patients), physician referral, or community cases during June 2016-June 2017. Pregnant women underwent fetal MRI or ultrasound during the second or third trimesters between 4 weeks and 10 weeks after symptom onset, with infants undergoing brain MRI and cranial ultrasound after birth.

Of those 82 pregnancies, there were 80 live births, 1 case of termination because of severe fetal brain abnormalities, and 1 near-term fetal death of unknown cause. There was one death 3 days after birth and one instance of neurosurgical intervention from encephalocele. The researchers found 3 of 82 cases (4%) displayed fetal abnormalities from MRI, which consisted of 2 cases of heterotopias and malformations in cortical development and 1 case with parietal encephalocele, Chiari II malformation, and microcephaly. One infant had a normal ultrasound despite abnormalities displayed on fetal MRI.

After birth, of the 79 infants with normal ultrasound results, 53 infants underwent a postnatal brain MRI and Dr. Mulkey and her associates found 7 cases with mild abnormalities (13%). There were 57 infants who underwent cranial ultrasound, which yielded 21 cases of lenticulostriate vasculopathy, choroid plexus cysts, germinolytic/subependymal cysts, and/or calcification; these were poorly characterized by MRI.

“Normal fetal imaging had predictive associations with normal postnatal imaging or mild postnatal imaging findings unlikely to be of significant clinical consequence,” they said.

Nonetheless, “there is a need for long-term follow-up to assess the neurodevelopmental significance of these early neuroimaging findings, both normal and abnormal; such studies are in progress,” Dr. Mulkey and her colleagues said.

The researchers noted the timing of maternal infections and symptoms as well as the Zika testing, ultrasound, and MRI performance, technique during fetal MRI, and incomplete prenatal testing in the cohort as limitations in the study.

This study was funded in part by Children’s National Health System and by a philanthropic gift from the Ikaria Healthcare Fund. Dr. Mulkey received research support from the Thrasher Research Fund and is supported by awards from the National Institutes of Health National Center for Advancing Translational Sciences. The other authors reported no relevant conflicts of interest.

SOURCE: Mulkey SB et al. JAMA Pediatr. 2018 Nov. 26. doi: 10.1001/jamapediatrics.2018.4138.