Zika virus is a novel teratogenic agent associated with cerebral anomalies. Because of the challenges associated with assessment of antenatal diagnosis and prognosis in fetuses, screening for other congenital infections mostly relies on ultrasound. We aimed to assess whether a similar approach might be adequate for Zika virus congenital syndrome provided that early markers of infection and adequate timing for screening are established.
For this case series we reviewed all pregnant women who had a laboratory-confirmed Zika virus infection in their first trimester or early second trimester and abnormal fetal ultrasound findings who were managed at the Pluridisciplinary Center for Prenatal Diagnosis of Martinique during the Zika virus epidemic (Jan 1, 2016, to Nov 10, 2016) in Martinique, a French Caribbean island. Ultrasound imaging was done with GE Healthcare Voluson E10 and E8 machines with abdominal and vaginal probes.
We analysed 14 cases of pregnant women with confirmed Zika virus infection and fetal abnormalities of the brain, and 31 ultrasound imaging results. Between 16 and 20 weeks of gestation, four (33%) of 12 fetuses had an abnormal ultrasound examination. Anomalies were detected in nine (90%) of the ten fetuses from whom ultrasound images were obtained between 20 and 24 weeks of gestation. All five remaining fetuses at 24-28 weeks of gestation, and all four after 28 weeks, had severe anomalies. Major anomalies identified were ventriculomegaly (12 fetuses, 86%), cortical atrophy (11, 79%), calcifications (ten, 71%; particularly located at the corticosubcortical junction), and anomalies of the corpus callosum (ten, 71%). Prenatal assessment of head circumference measurement by imaging was not an effective screening tool for congenital Zika virus infection, with microcephaly only identified in nine (64%) fetuses.
Ultrasound monitoring appears to be a good screening strategy to monitor Zika virus-exposed pregnancies. Public health efforts should focus on scanning at 22-26 weeks of gestation. Identification of ventriculomegaly, cortical atrophy, calcifications, and anomalies of the corpus callosum should prompt laboratory screening for Zika virus.
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