Unborn Babies may Contract COVID-19 Via Infected Mother
An unborn baby could become infected with COVID-19 if their gut is exposed to the SARS-CoV-2 virus, finds a new study led by UCL researchers with Great Ormond Street Hospital for Children and the NIHR Great Ormond Street Biomedical Research Centre.
Generally, the opportunities for the COVID-19 virus transmission in the fetus are extremely limited, as the placenta in the womb acts as a highly effective and protective shield.
‘Certain fetal organs, such as the intestine, and kidney are more susceptible to COVID-19 infection than others.’
In this new study published in BJOG, an International Journal of Obstetrics & Gynaecology, researchers set out to understand how newborn babies could have developed COVID-19 and wanted to know if the virus passed from an infected mother to the unborn fetus.
To answer this question, researchers examined various fetal organs and placenta tissue to see if there was any presence of the cell surface protein receptors, ACE2 and TMPRSS2. These two receptors sit on the outside of cells and both are needed for the COVID-19 virus to infect and spread.
They found the only fetal organs to feature both the ACE2 and TMPRSS2 were the intestines (gut) and the kidney; however, the fetal kidney is anatomically protected from exposure to the virus and is, therefore, less at risk of infection.
Therefore, they concluded that the COVID-19 virus could only infect the fetus via the gut and through fetal swallowing of amniotic fluid, which the unborn baby does naturally for nutrients.
After birth ACE2 and TMPRSS2 receptors are known to be present in combination on the surface of cells in the human intestine as well as the lung.
Senior author, Dr. Mattia Gerli (UCL Division of Surgery and Interventional Science & the Royal Free Hospital) explained: "The fetus is known to begin swallowing the amniotic fluid in the second half of pregnancy. To cause infection, the SARS-CoV-2 virus would need to be present in significant quantities in the amniotic fluid around the fetus.
However, many studies in maternity care have found that the amniotic fluid around the fetus does not usually contain the COVID-19 virus, even if the mother is infected.
This new study findings, therefore, explain that clinical infection of the fetus during pregnancy is possible but uncommon and that is reassuring for parents-to-be.
The biggest risk to the fetus during pregnancy is if the mother becomes very unwell with COVID-19 infection. In this instance, the virus may be present in high concentrations in the amniotic fluid. In addition, it could damage the placenta, which can lead to preterm birth.
Vaccination against COVID-19 is known to be safe in pregnancy and reduces the chance of infection to very low levels. The results of this study provide definitive information regarding the susceptibility of the human fetus to COVID-19 infection.
They also support current healthcare policy that vaccination in pregnancy is the best way for mothers to protect their unborn baby from COVID-19 infection.
Source: Medindia