A Mumbai-based security guard recently underwent a miscarriage, and studies show that it may have been caused due to an inflammation in the foetus, after the woman had been infected with the novel coronavirus. It adds that the virus spread to the foetus via the umbilical cord and placenta.

“To our knowledge, this is the first case demonstrating persistence of SARS-CoV-2 infection in a tissue weeks after clearance in the throat swabs… the virus not just survived in the tissue but is replicative in the placental cells,” stated a research paper submitted last week by the National Institute of Research in Reproductive Health (NIRRH) – a research arm of the Indian Council of Medical Research – in collaboration with ESIS (Employees’ State Insurance Scheme) hospital at Kandivali.

The woman had tested Covid-19 positive in the initial trimester of her pregnancy, and was found asymptomatic. During her 13th week of pregnancy, she tested herself and was found Covid-19 negative. Post the 13th week, when she went for her ultrasound test, the foetur was found to be dead, according to a report in The Indian Express.

The report adds that there ESIS hospital approached the NIRRH to investigate further, trying to link the miscarriage with Covid-19. The hospital’s ethics committee approved tests on the woman.

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“We first tested her nasopharyngeal for Covid-19 again, and it came negative. Then we tested the placenta, amniotic fluid and foetal membrane. We were surprised to find that five weeks after she got the infection, the virus was replicating in the placenta,” said Dr Deepak Modi, placenta biologist in NIRRH.

Doctors suspect vertical transmission of the virus which led to inflammation in the lungs of the foetus, and eventual death. Vertical transmission refers to Covid-19 spreading in-utero from mother to foetus and can cause a miscarriage. 

Doctors in Mumbai suspect a similar placenta infection leading to the miscarriage. “The placenta acts as a barrier protecting the baby from infections from the second and third trimester. But in the first trimester, it is still building as a barrier,” Modi said.

“We found that there is concentration of ACE-2 enzyme in placenta during the first trimester. It acts as a reservoir for SARS-CoV-2,” he added. ACE-2 acts as an entry point for coronavirus into a human cell and helps it replicate.

The research paper stated that this is the first time the virus was found replicating in the placenta five weeks after infection, resulting in foetal inflammation.