On 16 March, the Chief Medical Officer placed pregnant women on the list of persons vulnerable to coronavirus who should take extra precautions to protect themselves from possible exposure.
However, as the virus is relatively new, there is still not yet anything approaching a definitive body of evidence regarding how likely it is that a mother may pass the virus onto her unborn child in utero – something known as ‘vertical transmission’ – or indeed on how harmful such transmission might prove. This is why a new Italian study investigating the issue of in utero transmission should be considered important, despite its relatively small size and scope.
The study saw University of Milan researchers examine the pregnancies of 31 coronavirus-infected women for signs of in utero COVID-19 transmission. It is reported that they found signs of mother-to-baby transmission in most cases, with virus samples recorded in the placenta, the umbilical cord, the vaginal mucosa and, in one instance, breast milk.
Most of the maternal cases of infection involved in the study were classed only as mild. However, in the one more severe case examined by the study, the umbilical cord blood tested positive in an antibody test. This indicates that the baby, which also tested positive post-birth, had begun to develop its own antibodies.
The study’s lead researcher, Dr. Claudio Fenizia, an immunology specialist at the University of Milan, said that the study should not give cause for alarm, nor, he said, should it merit any changes in health guidelines or public policy.
Furthermore, he stated that fetal COVID-19 infection remains relatively rare and that even when it does occur it is unlikely to result in serious illness – the two newborns who tested positive for the virus during the study never became ill with it.
In fact, all the study really does is confirm what clinicians already believe to be true: vertical COVID-19 transmission is relatively rare and is unlikely to be serious.
The study does not change anything. As such it is still important to follow official health guidelines regarding coronavirus, i.e. to social distance, to wash hands and to work from home if you are able. However, such precautions do not mean you need to become a recluse during your pregnancy, only that you should take all reasonable precautions. It is also important to note that if you have recently been diagnosed with COVID-19 or you have any of the symptoms and are breastfeeding, you may wish to follow UNICEF’s advice to wear a mask while breastfeeding.
Professor Marian Knight, from the National Perinatal Epidemiology Unit and the University of Oxford is charged with the UK-wide surveillance of COVID-19 in pregnancy, and says that the Italian study fits with the emerging body of evidence regarding mother-to-child transmission.
“Around 2 per cent of babies of mothers admitted to hospital with Sars-CoV-2 in pregnancy in the UK have a positive test for the virus, but do not appear to become severely unwell,” she told The Telegraph. “Preventing infection through continued measures such as hand washing and social distancing in the third trimester are the most important actions for women,” she added.