Fetal abnormalities were detected among more than a quarter of pregnant women who underwent ultrasound examinations after testing positive for Zika virus infection.
The small study, which included 88 pregnant women enrolled from September 2015 through February 2016 in Rio de Janeiro, was published online March 4 in the New England Journal of Medicine (doi: 10.1056/NEJMoa1602412).
“Our findings provide further support for a link between maternal ZIKV infection and fetal and placental abnormalities that is not unlike that of other viruses that are known to cause congenital infections characterized by intrauterine growth restriction and placental insufficiency,” investigators from Brazil and California reported.
The women in the study had developed a rash within the previous 5 days and were tested for Zika virus infection using reverse transcriptase polymerase chain reaction (RT-PCR) assays. Of the 88 women tested, 72 (82%) tested positive for Zika virus in blood, urine, or both.
Acute Zika infection was found throughout the course of pregnancy, though more than half of the women presented with acute infection during the second trimester. Along with a macular or maculopapular rash with pruritus, other distinctive clinical features of Zika virus infection included conjunctival injection, lymphadenopathy, and an absence of respiratory symptoms.
Two women who were positive for Zika virus had miscarriages during the first trimester. The investigators performed ultrasound for 42 of the remaining 70 women who had tested positive for Zika virus, as well as all women who tested negative for the virus. The other women who tested positive for Zika virus declined the imaging studies.
Fetal abnormalities were detected in 12 (29%) of the 42 women who were Zika virus positive and none of the women who had tested negative.
Among the 12 fetuses with abnormalities, there were two fetal deaths noted on ultrasound after 30 weeks of gestation. There were five fetuses with in utero growth restriction with or without microcephaly on ultrasound. Four fetuses had cerebral calcifications, and other central nervous system alterations were noted in two fetuses. Ultrasound detected abnormal arterial flow in the cerebral or umbilical arteries in four fetuses. Also, oligohydramnios and anhydramnios were seen in two fetuses.
At the time of this report, there had been six live births and two stillbirths among the study cohort and the ultrasound findings had been confirmed. The study was not supported by any research funds. The investigators reported having no financial disclosures.
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