Pregnant women and their developing babies are at greater risk of serious consequences if they contract Covid-19, and now a large, international study is helping to underline just how devastating those risks can be.
The study is based on data from 12 studies from as many countries, including the United States. In total, the studies included more than 13,000 pregnant women – about 2,000 with a confirmed or probable case of Covid-19. The health outcomes for these women and their babies were compared to about 11,000 pregnancies where the mother tested negative for Covid-19 or antibodies at the time of their delivery.
In the studies, about 3% of pregnant women with Covid-19 required intensive care and about 4% required some form of critical care, but this was much higher than the number of pregnant women who required that type of care outside of a Covid-19 19 period at. 19 infection.
Compared to pregnant individuals who were not infected, those who contracted Covid-19 were almost 4 times more likely to be admitted to an intensive care unit. They were 15 times more likely to need a ventilator and 7 times more likely to die. They also had a higher risk of preeclampsia, blood clots, and problems caused by high blood pressure. Babies born to mothers who had Covid-19 were at greater risk of preterm birth and low birth weight.
Previous studies have suggested that Covid-19 may increase the risk of stillbirth, but this study did not find that same link.
Still, the findings paint a clear picture showing that the risks of pregnancy are amplified by Covid-19 infections.
“It’s very clear and even consistent, you know, whether we’re talking about Sweden, where we generally have really great pregnancy outcomes, or other countries that have bigger issues with maternal morbidity and mortality, that having COVID and pregnancy increases the risk for both mother and baby,” said lead study author Emily Smith, an assistant professor of global health at George Washington University.
The study has some caveats that may limit the applicability of the findings to pregnant individuals in the Omicron era.
First, the studies were conducted relatively early in the pandemic, at a time when most people were unvaccinated and uninfected. That means people in the study were likely at higher risk not only because they were pregnant, but also because they were immunologically naive to the virus — they had no pre-existing immunity to help them fight off their infections.
Since then, many pregnant individuals have been vaccinated, or have had Covid-19, or both. As of the first week of January, about 72% of pregnant people in the US have had their primary set of Covid-19 vaccines, and it is estimated that about 95% of Americans have had Covid-19 at least once or have been vaccinated against it, according to data from the Centers for Disease Control and Prevention. That means it’s likely they have an immune memory against the virus that could help protect against serious consequences.
However, that immune memory seems to fade over time. CDC data shows that only 19% of pregnant women have had an updated booster, meaning many people may not have as much protection against the virus as they think.
Lead study author Emily Smith, assistant professor of global health at George Washington University, says the study results reflect the risk of Covid-19 and pregnancy in unvaccinated people.
Unfortunately, Smith says, many countries still don’t have clear guidelines for vaccination during pregnancy. And there are some parts of the world, such as China, where a significant portion of the population has still never been infected.
For people trying to weigh the risks and benefits of Covid-19 vaccination during pregnancy, Smith says this study helps tip the scales firmly in the direction of vaccination.
“It’s worth protecting yourself during pregnancy,” Smith said.
She says this study did not look at the benefits of vaccination during pregnancy, but other studies have shown a large reduction in the risk of stillbirth, premature birth and serious illness or death for the mother.
“And so that’s kind of a complementary story,” Smith said.
Dr. Justin Lappen, division director of Maternal Fetal Medicine at the Cleveland Clinic, praised the study, saying the findings reinforce and advance previous research showing that Covid-19 significantly increases the risk of serious outcomes for mother and baby. He was not involved in the investigation.
He says the findings highlight the importance of preventing and treating Covid-19 in pregnant women.
Therapies indicated or otherwise recommended should not be withheld specifically because of pregnancy or breastfeeding, Lappen wrote in an email to CNN.
The study is published in the journal BMJ Global Health.