New research suggests that a woman’s second-trimester miscarriage was the result of a coronavirus-induced placental infection. According to a new report in the Journal of the American Medical Association, there have been reports of stillbirths and newborns with fetal distress that may be attributed to pregnant mothers contracting the coronavirus in the third-semester. Researchers said this suggests “the possibility of COVID-19–induced placental pathology.”

The report notes one March 2020 case of a miscarriage during a coronavirus-infected woman’s second trimester. In that case, the fetal autopsy showed no indications of the virus, but the placenta tested positive. “This case of miscarriage during the second trimester of pregnancy in a woman with COVID-19 appears related to placental infection with SARS-CoV-2, supported by virological findings in the placenta,” the report states. The report, which comes as obstetricians have reported an uptick in stillbirths during the pandemic, also noted that this infection in the placenta that resulted in miscarriage or impediment of fetal growth was found in at least 40 percent of cases of pregnant patients with MERS and SARS—which are both coronaviruses. “There was no evidence of vertical transmission, but the absence of the virus is not surprising given the stage of fetal development and short time of maternal infection,” the report added.