COVID-Linked Miscarriage Reported in Mumbai, But It May Be Rare

A woman from Mumbai suffered a miscarriage that may have been caused due to COVID-19, says a study.

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Coronavirus
4 min read
A woman from Mumbai suffered a miscarriage that may have been caused due to COVID-19.
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In what is being touted as the first such case in India, a woman from Mumbai suffered a miscarriage that may have been caused due to COVID-19.

A study by the National Institute of Research in Reproductive Health (NIRRH) in collaboration with ESIS (Employees’ State Insurance Scheme) hospital in Mumbai has linked the miscarriage to the disease. A preprint on the case published on 21 August stated, “Herein, we report a case of active SARS-CoV-2 viremia in the first trimester placental tissue five weeks after the asymptomatic mother cleared the virus from respiratory tract causing vertical transmission and fetal demise.”

“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 study also provides evidence for vertical transmission of the virus in the first trimester leading to fetal demise.”
Researchers

More About The Case

A first-trimester miscarriage in the woman in her late 20s was linked to the novel coronavirus after tests found the infection had travelled into the umbilical cord and the placenta, which may have caused inflammation in the foetus, reported The Indian Express.

The woman had a history of contact with a symptomatic COVID-19 positive patient when she was eight-weeks pregnant, after which she tested positive and was subsequently quarantined as per protocol. She remained asymptomatic throughout this period. Five weeks later, her ultrasound evaluation showed her fetus had died, suspectedly from inflammation. While she tested negative in the throat swabs, the virus may have travelled to the womb. In fact, it not just survived in the tissue, but was also found to be replicative in the placental cells.

Dr Deepak Modi, placenta biologist in NIRRH told The Indian Express,

“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.”
Dr Deepak Modi

Another instance where COVID-19 may have caused a miscarriage due to placental infection was reported in March in Switzerland, where the pregnant woman with COVID-19 gave birth to a stillborn child in her second trimester. However, authors of the research letter pertaining to this case wrote in the peer-reviewed journal JAMA that other causes of miscarriage, such as spontaneous preterm birth, cervical insufficiency, or undetected systemic or local bacterial infection, cannot be ruled out. Regardless, no other cause of fetal demise had been identified.

Are We Missing Out Miscarriages Caused Due to COVID-19?

There exists restricted evidence for vertical transmission of the virus, as we will discuss, but cases of miscarriages appear to be extremely unusual. There isn’t enough information on the virus’ effect on fetuses.

Experts at NIRRH have shared their concerns about insufficient tests done among pregnant women in their first trimesters. Speaking to The Indian Express, Dr Rahul Gajbhijiye said that even though the institute has been maintaining a registry of pregnant women infected with the disease in Maharashtra, these cases are usually recorded in the third trimester or after the delivery.

“COVID-19 infected pregnant women are mostly asymptomatic. We only diagnose them when they come for delivery and get tested. It is possible we are missing miscarriages in first trimester linked with COVID-19 because no tests are being conducted in the first two trimesters.”
Dr Rahul Gajbhijiye

Further studies are required to throw more light on vertical transmission of the virus in the first trimester so that universal screening of all pregnant women can be considered in such cases to avoid any adverse fetal outcomes.

Vertical Transmission: What We Know So Far

The study authors for the Mumbai case wrote, “While the modes of human to human transmission of SARS-CoV-2 is well established, controversy exists regarding the transmission of the virus from mother to unborn fetuses.”

Even though cases of vertical transmission have been reported globally, they are known to be rare.

According to the CDC, “Limited reports in the literature have raised concern of possible intrauterine, intrapartum, or peripartum transmission, but the extent and clinical significance of vertical transmission, which appears to be rare, is unclear.”

“Most newborns who have tested positive for COVID-19 had mild or no symptoms and have recovered fully,” it adds.

Speaking to FIT, Dr Suhasini Inamdar, Consultant, Obstetrics and Gynecology, Motherhood Hospitals, Bengaluru, said it may be too soon to make generalisations as studies are still ongoing to evaluate the ways in which the virus could affect pregnancy and fetuses. On transmission from mothers to the babies, she said that so far, it is uncommon for newborns to test positive for the virus. “This particular case could be an unusual incident where we saw a lot of virus in the placenta.”

Certainly, the possibility cannot be denied. Reports of newborns having contracted the infection from COVID-19 positive mothers have been coming in from various places, including Bengaluru (in this case, it may also be attributed to post-delivery factors; like the woman not wearing masks while feeding). Dr Inamdar says,

“Coronavirus is highly contagious because it keeps mutating very fast. Placenta can be an ideal place for the virus to enter and replicate because it has plenty of blood supply and enzymes in it. Since COVID-19 is new, a lot of data collection and research needs to be done to understand further.”
Dr Suhasini Inamdar

A research article from August, in fact, found that 12% (11/93) of placentae obtained from mothers with COVID-19 had detectable levels of the virus RNA.

During pregnancy, the placental barrier protects the fetus from pathogens and ensures healthy development. Dr Inamdar, however, warns, “But it is not a full-proof filter. It may not be capable of filtering out certain viruses, and the novel coronavirus may be one of them.”

It is known that pregnancy could boost the risk of serious disease from respiratory viral infections, as our experience with H1N1 and SARS showed. But for COVID-19, such complications appear to be rare, until we obtain further information.

For more clarity on placental infection, Wadia hospital with NIRRH will assess 100 pregnant women to check whether their placenta has coronavirus after delivery. Researchers will also be looking at the registry of COVID-positive women in Maharasthra, to study how the virus affects pregnancies, fetus, newborns and the mothers in the post-partum period, IE reported.

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