A US research team has examined whether a corona infection in the mother during pregnancy affects the health of the unborn child. The results have now been presented – and heavily criticized.

How dangerous is a corona infection in the mother for the unborn child? A question that has occupied science since the beginning of the pandemic. A new study has now been presented in the specialist magazine “Jama Network Open”, which examined the neurological development of the child within the first year of life. However, experts are very critical of the results.

For the study, the US research team compared two cohorts, including 222 babies whose mothers contracted Covid-19 during pregnancy and 7,550 babies whose mothers were not infected during pregnancy. All births took place between March and September 2020. At a time when there was no vaccination against the corona virus. 14 of the 222 babies were diagnosed with a neurodevelopmental disorder. That’s 6.3 percent. Of the babies whose mothers got through the pregnancy corona-free, it was 3 percent (227).

The data comes from six hospitals. The researchers want to see in this result preliminary indications that the infection during pregnancy could cause neurological impairments in some children. But the study has a number of limitations.

Experts see “no evidence” of a connection

“On the basis of this study, it is not possible to conclude that COVID-19 causes developmental problems in children during pregnancy,” said Marian Knight of the University of Oxford, whose specialist prayer is maternal and child health. She explains that there are a number of possible explanations for these results. For example, women who are hospitalized due to pregnancy complications are more likely to be tested for corona infection. The probability is therefore higher that an infection will also be detected in this group, whose risk is already increased – “even if it [the corona infection] has no effect on their pregnancy”.

In addition, the study authors only listed a limited number of pregnancy complications. She says: “Differences in the frequency of other pregnancy complications could explain the results more than a Sars-CoV-2 infection.”

Dimitrios Siassakos, Professor of Obstetrics and Gynecology, University College London, takes a very similar view of the study. There is no evidence, he says, that a mother’s Covid-19 infection leads to neurodevelopmental problems in the babies. It is “just as likely, if not more likely,” that the women in the study who tested positive — regardless of Covid-19 — have some characteristics that are linked to later problems in their offspring.

Other explanations for neurological disorders possible

While it has not yet been clarified whether Covid-19 harms the baby directly, we now know for sure that gestational diabetes, for example, does exactly that. Especially if it is not diagnosed and treated. “It’s possible that undiagnosed diabetes is the hidden culprit,” Siassakos said. He also concludes: “There is no evidence that this connection is causal [to neurological disorders], that Covid-19 leads directly to these problems.”

Knight points to another possible explanation for the US researchers’ discoveries. Many babies in the study were therefore born prematurely. “We know that vaccination protects pregnant women from severe Covid-19 disease and also reduces the likelihood of preterm birth,” she says. And: “Full vaccination is the best thing women can do to protect their baby from the adverse effects of Covid-19 disease.”

Corona vaccination protects

A study by the University of Edinburgh showed how dangerous it can be if pregnant women are not vaccinated (more on this here). There, the scientists analyzed data from women who became pregnant between March 2020 and October 2021, including 4950 who were proven to have been infected with the corona virus. A large proportion of the infected women, more than 77 percent, were therefore unvaccinated. And: Every fifth pregnant woman who was not vaccinated fell ill so severely with Covid-19 that she had to be treated in the hospital.

By way of comparison, only one in 20 pregnant women who had breakthrough vaccinations had to go to the hospital. The numbers from the intensive care units are even clearer. Almost all pregnant patients who needed intensive medical care were unvaccinated – 98 percent according to the study. A woman died. The German Society for Gynecology and Obstetrics has been recommending corona vaccination for pregnant women since May 2021, and the Standing Vaccination Committee followed in September.

Another study, published in the journal Jama Pediatrics in January, examining whether a mother’s corona infection during pregnancy affected the neurological development of the infant points in a different direction to the recently published study. Babies aged six months were examined as part of the study. According to the research team, the results indicate that the time of birth, i.e. during the corona pandemic, had an impact on the neurodevelopment of the children. The corona infection of the mothers probably had no effect.

Source: Jama Network, study preprint, Jama Pediatrics, citations provided by Science Media Center Germany and Science Media Center UK