Birth Defects Among Fetuses and Infants of US Women With Evidence of Possible Zika Virus Infection During Pregnancy

Abstract

(JAMA. 2017;317(1):59–68) Fetal microcephaly and other brain abnormalities have been associated with Zika virus infection during pregnancy. However, the magnitude of risk for fetuses of infected parturients remains unknown. It is also unclear whether women with symptomatic Zika virus disease are more likely to have adverse pregnancy outcomes than those with asymptomatic infection. This report analyzed data obtained from the US Zika Pregnancy Registry (USZPR) to determine the proportion of fetuses or infants with birth defects likely to be associated with maternal Zika virus infection among women in the United States. The investigators also evaluated whether the proportion of infants with birth defects differed based on the presence of maternal symptoms of Zika virus infection or by trimester of possible infection.

Zika Virus —10 Public Health Achievements in 2016 and Future Priorities

“…The proportion of completed pregnancies affected by birth defects was similar following either symptomatic or asymptomatic infection during pregnancy (32). This estimate is consistent with models based on the outbreak in Bahia, Brazil, which estimated a 1%-13% risk for microcephaly after a Zika virus infection during the first trimester (33).…”

“…Hawaii suggest that among pregnant women with laboratory evidence of possible Zika virus infection, approximately 6% of fetuses or infants have a birth defect potentially related to Zika virus, and among women with first-trimester Zika infection, 11% of fetuses or infants have evidence of Zika-associated birth defects (32). The proportion of completed pregnancies affected by birth defects was similar following either symptomatic or asymptomatic infection during pregnancy (32).…”

Vulnerability of primitive human placental trophoblast to Zika virus

“…However, there have been reports of fetal brain ultrasound anomalies and abnormal brain development in women considered to have become infected by ZIKV late in their pregnancies (5,16). On the other hand, the overall risk for microcephaly and other brain abnormalities in infants born to a larger cohort of US women exposed to ZIKV (n = 442) was 5.9% (17), and, of these, there were no cases noted among the women known to have been infected during their second or third trimesters. Clearly, there remains some uncertainty regarding the consequences of maternal ZIKV infection in the later stages of pregnancy.…”

Toxoplasmosis Molecular Testing Discrepancy in a Case of Asymptomatic Microcephaly

“…It is important to mention that the ideal method for diagnosing Zika virus infection would have been serology, but this was not available. The PCR for Zika virus is known to be positive for a short period of time, therefore its negativity does not exclude the diagnosis [10]. However, in the absence of compatible epidemiology, other symptoms or dysmorphisms of the Congenital Zika virus Syndrome, this differential becomes unlikely.…”