Newborns steer clear of mom’s COVID-19
Study of third-trimester infections shows fetuses avoiding virus
Anew study may prove reassuring for expectant moms: Pregnant women who are infected with
COVID-19 during their third trimester appear unlikely to pass the infection to their fetuses.
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This study was conducted between
April and June 2020 among women who came to one of three Boston area hospitals either for treatment of COVID-19 or for delivery. ■ None of the newborns of the 127 pregnant women, including 64 who had varying levels of illness from the virus, tested positive for the coronavirus.
“I think that’s probably one of the more reassuring pieces to a patient, just that if you get COVID-19 in pregnancy, still there seems to be a relatively low chance that your fetus is going to be born with active COVID-19 infection,” said study author Dr. Andrea Edlow, a maternal-fetal medicine specialist at Massachusetts General Hospital.
The study participants who had tested positive for COVID-19 included 36 percent who were asymptomatic, 34 percent who had mild disease, 11 percent who had moderate disease, 16 percent with severe disease and 3 percent with critical disease.
The study also included 63 pregnant women who tested negative for the virus and 11 reproductive-age women who were not pregnant, to provide comparison.
Researchers evaluated the levels of virus in respiratory, blood and placental
“I think that’s probably one of the more reassuring pieces
tissue samples. They also looked for the development of maternal antibodies and how well those antibodies passed through the placenta to the fetus and examined placental tissue.
They found detectable levels of the virus in the women’s saliva, nasal and throat secretions. They found no virus in the bloodstream or the placenta.
Though in this study none of the babies were born positive for COVID-19, the risk isn’t zero, Edlow cautioned. Other studies have shown the range is quite low, however, much lower than in other viruses, including Zika or cytomegalovirus, she noted.
Another significant but less encouraging finding from the study is that the moms infected with COVID-19 did make antibodies to the virus but did not transfer them across the placenta as much as would be expected.
While finding lower
to a patient, just that if you get COVID-19 in pregnancy, still there seems to be a relatively low chance that your fetus is going to be born with active COVID-19 infection.”
Dr. Andrea Edlow, study author and maternal-fetal medicine specialist at Massachusetts General Hospital.
than-expected levels of protective antibodies in umbilical cord blood, researchers found high levels of inf luenza antibodies, possibly from maternal f lu vaccination, according to the study. In other viruses or vaccines, antibodies tend to be transferred at much higher levels, possibly for evolutionary reasons because babies can’t develop their own antibodies until 6 months of age, Edlow said.
The study was published Dec. 22 in the journal JAMA Network Open.
The new findings may have implications over how the new COVID vaccine can affect pregnancy, according to an editorial accompanying the study.
“I don’t think it’s definitive, but it raises unanswered questions about whether maternal antibodies from COVID vaccination are going to help protect the baby the way we see with, for example, inf luenza vaccine,” said editorial coauthor Dr. Denise Jamieson, chair of the department of gynecology and obstetrics at Emory University School of Medicine in Atlanta.
The findings highlight the importance of ensuring that pregnant women are included in research, Jamieson said, because scientists need to better understand how medication and vaccines work specifically in pregnant women.
“I think it’s a really exciting time. I think we now have the tools to end this pandemic. It’s going take some time, and in the meantime, pregnant women need to be vigilant and continue to protect themselves, but I’m very optimistic knowing that pregnant women are going to have access to these [COVID] vaccines,”
Jamieson said.
Although children overall have more mild disease when contracting COVID-19, infants are at higher risk for severe disease. Pregnant women are also at increased risk of severe disease.
The researchers hope to follow up with the women from this study and their children in future research.
The World Health Organization offers additional information on COVID-19 and pregnancy at www.who.int.