As health care officials continue to learn about and manage the COVID-19 pandemic and its increasingly widespread impact as a potentially severe respiratory infection worldwide, there is some encouraging news for pregnant women who may be exposed to the SARS-CoV-2 virus that causes the disease. According to a new observational study on women with COVID-19 in their third trimester of pregnancy, the virus does not appear to travel across the placenta from mother to cause infection of the fetus. An early online release of the study is published in Archives of Pathology & Laboratory Medicine, the monthly international peer-reviewed journal of the College of American Pathologists (CAP).
The observational study included 38 documented cases of pregnant women in China diagnosed with COVID-19. All women, between the ages of 26 and 40, were in their third trimester when they developed the infection. The author assessed the effects of the coronavirus on both the mothers and infants, and in particular, whether the newborn infants developed the infection prior to birth.
“So far, preexisting health problems do not seem to be a risk factor that would contribute to maternal-fetal viral transmission or to greater baby or maternal deaths among pregnant women with COVID-19,” says David A. Schwartz, MD, MS Hyg, FCAP, a CAP Fellow and pathologist with Augusta University specializing in global maternal health and obstetric and placental pathology. He is also a medical epidemiologist, studying origins, incidences, distribution and possible control of disease.
Of the 38 pregnant women, none had a preexisting chronic illness, but several did develop complications during pregnancy that included influenza, gestational hypertension, preeclampsia, gestational diabetes and preterm labor. Some exhibited symptoms such as cough, sore throat, muscle pain, discomfort, gastrointestinal symptoms and shortness of breath. None of the women developed severe pneumonia or required intensive care.
It is typical for changes that normally occur in pregnant women to increase their risk of developing respiratory viral infections. Previous outbreaks of different coronaviruses—severe acute respiratory syndrome (SARS) in 2002-2003 and Middle East respiratory syndrome (MERS) in that began in 2012—increased the risk to pregnant women of having obstetrical complications including pneumonia, early pregnancy loss, and even death. However, there were no women with SARS or MERS where the virus was passed through the placenta from mother to baby.
Significantly, as of the observational study’s publication date, there were no confirmed cases of prenatal transmission of SARS-CoV-2 from mother to infant. In those cases where amniotic fluid, placentas, umbilical cord blood and throat swabs of newborns were tested, all were negative for the virus despite some cases of pre- and post-birth complications. Fortunately, in the 38 women evaluated in this article, COVID-19 does not appear to cause maternal death. However, analysis of additional cases is necessary to determine if this remains true.
Whereas some viral infections can threaten the health and survival of both infected mothers and fetuses, notably the Ebola virus, and other viruses can cause fetal malformations or death such as the Zika virus and rubella (German measles), there is currently no documented evidence for COVID-19 causing any of these outcomes in pregnant women or fetuses. It remains unknown what, if any, effects COVID-19 may have on the fetus in early pregnancies.
Dr. Schwartz studies and has published research on the origins and emergence of the Zika and Ebola viruses and the impact of infection during pregnancy.
Pathologists are medical doctors who are critical members of the health care team, combining a scientist’s understanding of what laboratory evidence suggests and a specialty physician’s knowledge of medicine to determine the correct diagnosis. As the international health emergency continues to evolve, the public should follow the Centers for Disease Control and Prevention’s (CDC) recommendations for prevention and treatment of the COVID-19 disease.