Could an Inherited Virus Predispose Women to Preeclampsia?

Preeclampsia occurs in ≈6% of pregnancies and elevates risk for maternal and fetal mortality. Investigators in the U.K. hypothesized that viral infection could be an underlying cause of preeclampsia. They looked for microbial mRNA (indicative of active viral replication) in the placental tissue of 99 women with preeclampsia and in 132 women without preeclampsia.

The only actively replicating microbes that distinguished women with preeclampsia from those without preeclampsia (controls) were human herpesvirus (HHV)-6A and HHV-6B. More women with preeclampsia than controls were HHV-6 positive (6.1% vs. 2.2%). Among the HHV-6–positive women, 70% had an inherited form of the virus. (About 1% of people are born with the full genome for one of thes…