Covid-19 reduces placenta’s immune response, study suggested

20 September, 2022 | Vaishali Sharma

Covid-19 covid-19

According to one study, if a pregnant woman contracts COVID-19, the infection, no matter how little, impacts the placenta’s immune response to future infections. The study was published in th...

According to one study, if a pregnant woman contracts COVID-19, the infection, no matter how little, impacts the placenta’s immune response to future infections.

The study was published in the American Journal of Obstetrics & Gynecology. “This is the largest study to date of placentas from women who had COVID-19 during their pregnancies,” said Dr Kristina Adams Waldorf, senior author and professor of obstetrics and gynaecology at the University of Washington School of Medicine.

“We were surprised to find that women who had COVID-19 during their pregnancies had placentas with an impaired immune response to new infection.”

This discovery, according to Adams Waldorf, “was the tip of the iceberg” in terms of how COVID-19 can alter foetal or placental development.

Because there were so few kids born with COVID-19 infection early in the pandemic, many people believed that COVID-19 did not appear to harm the developing baby.

“But what we’re seeing now is that the placenta is vulnerable to COVID-19, and the infection changes the way the placenta works and that in turn is likely to impact the development of the fetus,” Adams Waldorf said.

“To date, the studies about how COVID-19 might affect fetal or child development are very limited as the children are still very young,” noted co-author Dr Helen Feltovich, professor and associate medical director for maternal-fetal medicine imaging at Intermountain Healthcare in Utah.

“Our study suggests that babies born to mothers infected with COVID-19 at any point during their pregnancy will need to be monitored as they grow up,” she said.

The placenta provides nourishment, oxygen, and immune protection for the fetus until the time of birth. Studies led by Adams Waldorf have shown that women who contract COVID-19 have a significantly higher mortality rate than do women who do not contract COVID-19. Other studies have found that pregnant women are more likely to risk hospitalizations or preterm birth, according to the Centers for Disease Control and Prevention.

It’s unknown how different COVID-19 variants may affect the mother or fetus, Adams Waldorf and Feltovich agree.

“Studying each of the variants in real-time is really challenging,” Adams Waldorf said, “because they just keep coming so fast, we can’t keep up. We do know that the COVID-19 Delta variant was worse for pregnant individuals because there was a spike in stillbirths, maternal deaths and hospitalizations at that time.”

Regardless of the variant, Adams Waldorf stressed it’s important that women not catch COVID-19.

Women who are pregnant should first get vaccinated and boosted, and continue to mask and stay within a strict bubble of individuals who are also vaccinated and boosted. She acknowledges that may mean isolating for the duration of the pregnancy.

“The disease may be mild, or it may be severe, but we’re still seeing these abnormal effects on the placenta,” she said. “It seems that after contracting COVID-19 in pregnancy, the placenta is exhausted by the infection, and can’t recover its immune function.”

A total of 164 pregnant women were evaluated in this study, with 24 uninfected healthy patients serving as a control group and 140 women infected with COVID-19. Both groups gave birth at the same time, between 37 and 38 weeks. When patients with COVID-19 were compared to those without, preterm delivery occurred at nearly three times the rate. According to the research, over 75% of COVID-19 patients were either asymptomatic or had moderate symptoms.

Placental tissues were collected with patient consent from the Intermountain Healthcare Research Institutional Review Board in Salt Lake City, Utah, or the University of Washington Human Subjects Division in Seattle, Washington. Medical personnel gathered placental tissues at the time of birth.


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