Link between Covid-19 and stillbirth confirmed by major Irish study

A major international study has confirmed findings first made by Irish scientists about a link between Covid-19 infection in pregnant women and stillbirth.

According to the Irish Times, the study looked at 68 perinatal deaths in Ireland and 11 other countries and found 65 were caused by inflammation of the placenta linked to Covid-19 infection. The study, published this month in Archives of Pathology & Laboratory Medicine, found that in more than three-quarters of the cases, the placenta was severely damaged and unable to deliver oxygen and nutrients to the growing baby.

The babies examined for the study were either stillborn or died within seven days of being born, and all the mothers were unvaccinated and had been infected with coronavirus while pregnant.

Damage to placenta

When pregnant, the placenta supplies nutrients and oxygen to the foetus in the womb. According to the researchers, damage to a small part of the placenta does not necessarily result in complications for a pregnancy, but in the instances they studied, the damage was so widespread that in some cases, more than 90 percent of the placenta was dead. The reason? Placentitis.

According to the research, one factor behind SARS-CoV-2 placentitis is a build-up of a protein called fibrin, which causes clotting in the placenta. The condition can also involve the death of protective cells and unusual inflammation in the placenta.

Unvaccinated mothers deemed higher risk

At the start of the Covid-19 pandemic, there were no indications that pregnant women were at any greater risk from infection than other women, but as new variants spread the virus was linked to adverse outcomes in pregnancy.

In January last year, doctors in Cork University Hospital (CUH) published the first report of Covid-related placentitis, and in April that year the Royal College of Physicians in Ireland (RCPI) issued a statement about the first cluster of cases reported worldwide.

The RCPI detailed six cases of stillbirth and one miscarriage caused by SARS-CoV-2 in Ireland over the preceding four months, all related to the Alpha variant of the virus.

Experts and researchers in other countries were at first sceptical of the Irish findings, as other viruses are known to attack the foetus, but in this instance, it appeared the stillbirths were the result of an attack on the placenta.

However, the association between Covid-19 infection and stillbirth was confirmed last November by the US Centers for Disease Control and Prevention, which found pregnant women with the virus had an increased risk of stillbirth compared with uninfected women.

Currently, at least 18 Irish cases of Covid-related placentitis resulting in stillbirth have now been identified in CUH and the Rotunda Hospital in Dublin. All involved women who were not vaccinated.

“We’ve seen how the stillbirth birth rate increased during the pandemic with the Alpha and Delta waves of the virus,” Prof Keelin O’Donoghue, consultant obstetrician at CUH, told the Irish Times.

“We don’t know yet about the possible impact of Omicron.”