Study shows risk of mother-to-child transmission of COVID-19 virus

MANILA — A new study shows the potential risk of in-utero mother-to-child transmission of SARS-CoV-2, the COVID-19 virus, although one of the study’s authors said further studies are needed to draw a definitive conclusion.

The study, presented on Thursday at the AIDS 2020 virtual conference and on the eve of the July 10 international COVID-19 conference, collected specimens from 31 pregnant women who gave birth between March and April 2020 in Northern Italy. The specimens, which included vaginal swabs, tissue samples from the women’s placenta, umbilical cord, umbilical cord blood, amniotic fluid, and breast milk, were tested for the presence of severe acute respiratory syndrome coronavirus 2 — the virus causing COVID-19.

The results showed one case of the virus found in the vaginal mucosa, one case of the virus found in breast milk, and two cases where the babies tested positive for the virus via nasopharyngeal swabs, said Claudio Fenizia, assistant professor and researcher at the University of Milan’s Department of Pathophysiology and Transplantation, and one of the study leads.

In one of the babies that tested positive, the authors also found the virus in the placenta specimen and umbilical cord blood. In the other infant that tested positive, they also found the virus in the placenta, and immunoglobulin M antibodies in the umbilical cord blood.

“These two cases are strongly suggestive of in utero vertical transmission [of SARS-CoV-2]. However, these two babies were born healthy and [don’t have] any problem,” Fenizia told Devex.

The impact of the novel coronavirus on pregnancy has not been widely studied to date, and most that research so far are small studies involving few participants. In some studies, babies have tested positive for the virus after delivery, but questions remain as to whether the babies got the virus in-utero or after birth. According to the U.S. Centers for Disease Control and Prevention, a lot is still unknown about the risks of COVID-19 to newborns. While some newborns have tested positive for COVID-19, most have mild or no symptoms.

While they were able to find evidence of the virus in several specimens, Fenizia cautioned against drawing broad conclusions from the study, and recommends the issue be studied more extensively.

“I would say that the impact of the virus on pregnancy is not really widely studied,” he said. “I wouldn't draw a conclusion and defining new guidelines because of our study, but really … I would like to raise awareness about this particular topic that I feel [is] kind of underestimated right now,” he added.

He said research should be done on the impact of the virus across the various gestational stages. Their study was only able to take samples from women who were already in the late stages of pregnancy.

“We are trying to collect samples from women who are ... delivering now, but were infected earlier on during the pregnancy such that we can assess [what] is the impact of getting COVID-19 infection, not [just] during the last week of pregnancy,” he said, although he also noted it won’t be easy to track pregnant women who got infected with the virus months ago.

Assessing the risks is important, especially as there are currently no proven therapeutics against COVID-19, Fenizia said.

“What we can do? I think that the best we can do is prevention in particular for pregnant women, and they should follow safety rules that they should have been already following,” he said.

The study’s preprint will be published in MedRxiv, and the study authors are hoping for the peer-reviewed version to be “out soon.”