No evidence of mother-to-child COVID-19 transmission: study

Preliminary findings indicate that the novel coronavirus (COVID-19) may not be passed from mother to child late in pregnancy, according to a study published in the journal The Lancet Wednesday.

As limited data is available for pregnant women with COVID-19 pneumonia, the study aimed to evaluate the clinical characteristics of COVID-19 in pregnancy and the intrauterine vertical transmission potential of COVID-19 infection.

Researchers from Zhongnan Hospital of Wuhan University and Peking University First Hospital assessed the clinical records of nine women in late-stage pregnancies who had pneumonia caused by COVID-19.

All nine had liveborn infants, and researchers tested samples of amniotic fluid, cord blood, neonatal throat swabs and breast milk from six of the nine cases. The samples were collected in the operating room at the time of birth to guarantee that samples were not contaminated.

All infants and samples tested negative for the virus, and findings from this small group of cases suggested that there is currently no evidence for intrauterine infection caused by vertical transmission in women who develop COVID-19 pneumonia in late pregnancy.

Researchers explained that future follow-up of the women and children in the study will be necessary to determine their long-term safety and health. They caution that their findings are based on a limited number of cases over a short period of time and only included women who were late in their pregnancy and gave birth by cesarean section.

The study comes after the news of a newborn being infected with COVID-19 just 30 hours after being born on February 2.

Zhang Yuanzhen, one of the researchers, said as many important clinical details of this case are missing, it can not be concluded from this one case whether intrauterine infection is possible.

"We should continue to pay special attention to newborns born to mothers with COVID-19 pneumonia to help prevent infections in this group," Zhang said.

In an accompanying comment, Qiao Jie from the Peking University Third Hospital said the research provides insight into the clinical characteristics, pregnancy outcomes and vertical transmission potential of COVID-19 infection in pregnant women.

"Although the study analyzed only a small number of cases, under such emergent circumstances these findings are valuable for preventive and clinical practice in China and elsewhere," Qiao said.