Pregnant women walking in Hong Kong, March 2020
Anthony Wallace/AFP via Getty Images
Getting pregnant in the midst of the Covid-19 pandemic has been extremely challenging. Many had to give birth without a partner present, and new parents found themselves trapped with little or no outside support. In addition to this, there was also fear of the new coronavirus infection itself. At the beginning of the pandemic, there was little information about how the infection would affect pregnancies and newborns. But three years later, we have a clearer picture, and we are supporting vaccinations in particular.
The pandemic has definitely affected pregnancy negatively. A 2022 US study followed 1.6 million pregnant women in 463 hospitals, with half of the pregnancies occurring during the pandemic and the rest occurring in the year before the pandemic began. Maternal mortality was higher during the pandemic, with 8.69 deaths per 100,000 pregnancies compared to 5.17 deaths per 100,000 pregnancies. Statistical analysis shows that this was no accidental discovery.
A study published in January compared 115 babies born before the pandemic with 115 babies born to mothers who contracted COVID-19 during pregnancy. Thirteen of the pre-pandemic babies did not reach the expected developmental milestones between six and eight months of age, whereas none of the pre-pandemic babies. Whether the negative results are due to the virus itself or to the experience of pregnancy and childbirth during the period of viral infection. Pandemics and other factors are not entirely clear. “We were fighting an enemy we had never seen before, and we didn’t have much time to think about it,” says Alessio Fasano of Harvard Medical School.
We know that pregnant people are less likely than others to become infected with the SARS-CoV-2 coronavirus, but if they do become infected, they may be at greater risk. The 2022 review summarized 435 studies of about 3.2 million women with COVID-19. Pregnant or recently pregnant women were more likely than other women to be admitted to an intensive care unit and put on invasive ventilation.
Several systematic reviews have also suggested that covid-19 is associated with an increased risk of adverse pregnancy outcomes. A review of 42 studies involving 438,548 pregnant women found that infection during pregnancy was associated with an increased risk of preeclampsia, premature birth, and stillbirth. A 2022 study of 3,545 women in the United Kingdom found that first-trimester infection was associated with an increased risk of miscarriage, with 14% of women self-reporting the infection. , the percentage of uninfected women was found to be 8%. t.
However, stillbirth rates, for example, may be higher in SARS-CoV-2, but remain low overall. One analysis found 6 stillbirths per 1,000 pregnancies in people without covid-19, compared to 13 stillbirths per 1,000 pregnancies in those with covid-19. .
In premature birth, the timing of infection appears to be key. A 2022 study found that infection with SARS-CoV-2 within the first 27 weeks of pregnancy was not associated with preterm birth, but infection after 34 weeks was associated with a seven-fold increased risk. .
Overall, the third trimester of pregnancy seems to be the most risky. “Probably because the uterus is pressing on the lungs more heavily than in early pregnancy,” says Asma Khalil of St. George’s University Hospital in London.
There is no evidence that the virus itself is the cause, especially when it comes to premature birth, and the increased risk is probably due to medical intervention, Khalil said. “If the mother is unwell, doctors are more likely to deliberately deliver the baby early so that the mother can be treated more effectively.”
The good news is that the covid-19 vaccine is also effective during pregnancy. A 2022 review summarized evidence from 25 studies and found “overwhelming support” for vaccination during pregnancy to reduce the risk of infections and serious illness.
In a 2021 study, researchers led by Ran Bariser of the Clarit Institute in Tel Aviv, Israel, found 10,861 pregnant women who were vaccinated during pregnancy and 10,861 who were not vaccinated. compared. No one had previously been infected with covid-19. Among vaccinated participants, vaccination was 96% effective against infections, 97% against specifically symptomatic infections, and 89% against hospitalizations.
A 2022 review led by Khalil found that vaccination also benefits the fetus, reducing the risk of stillbirth by 15 percent. That protection is passed on to the newborn. A March study found that getting vaccinated during pregnancy reduces the chances of an infant contracting the novel coronavirus in the first six months of life.
Along with the efficacy of the vaccine, its safety has also been proven. In two 2022 studies, Decane Fell and her team at the Children’s Hospital of Eastern Ontario in Canada followed people who were vaccinated during pregnancy. One study followed 97,590 women who gave birth between December 2020 and September 2021, of whom nearly a quarter received at least one vaccination during pregnancy. These participants did not have an increased risk of negative pregnancy outcomes, such as bleeding or admission to the neonatal intensive care unit.
In another study, the team tracked 85,162 births. Just over half of the pregnant women received the vaccine during pregnancy, but there was no increased risk of premature birth or stillbirth.
Despite the vaccine’s benefits, there is debate about whether to offer boosters to pregnant women. A 2023 study showed that these caused strong antibody responses in pregnant women. Meanwhile, a February study by Sarah Jorgensen of the University of Toronto and her colleagues found that a third dose of the vaccine during pregnancy further protected infants against the dominant ommicron variant.
Countries such as the UK, US and Australia encourage pregnant women to be vaccinated against SARS-CoV-2, but there are no programs offering a COVID-19 booster during pregnancy. .
Since the covid-19 vaccine was first introduced, the debate over whether to vaccinate during pregnancy has been controversial, leading to poor communication and confusion. In 2021, Khalil and his colleagues found that less than a third of eligible pregnant women received the COVID-19 vaccine. A review published in February 2023 found that pregnant women remain less likely to accept the vaccine than nonpregnant women.
There is no doubt that pregnant people suffer as a result. In February 2022, data from six European countries showed that serious COVID-19 infections during pregnancy were “almost confined to unvaccinated women”.
Early in the pandemic, doctors weren’t sure if vaccination during pregnancy was the best option, Jorgensen said. However, this is not limited to the new coronavirus infection. Pregnant women are often excluded from clinical trials, and the safety and effectiveness of new drugs and vaccines in these people is uncertain. In a 2021 study, Jorgensen and colleagues looked at 376 trials published between 2017 and 2019, but only 5.3% included pregnant women.
In the midst of COVID-19, Harriet Van Spall of McMaster University in Ontario, Canada, said in a paper that excluding these participants from vaccine trials was a “missed opportunity.” . Admittedly, dealing with pregnant people is a delicate thing, says Katie Long of King’s College London. But as a result, coverage of life-saving vaccines appears to be declining.
Can the SARS-CoV-2 coronavirus infect the fetus during pregnancy?
Early in the pandemic, researchers wondered if the coronavirus could cross the placenta and infect the fetus. Initial reports suggested it was unlikely, but towards the end of 2020, Katie Long of King’s College London and her colleagues used samples from aborted pregnancies to test the fetus. I noticed a hemorrhage in the brain cortex.
“We found that bleeding was consistently associated with the presence of SARS-CoV-2 in fetal brain tissue,” she says. They concluded that the virus had entered the fetus and weakened blood vessels in the developing brain.
This was a dramatic finding, but we don’t know if the bleeding had any adverse effects on the developing fetus. There was no indication in the clinical record that COVID-19 was a contributing factor to the abortion. Nevertheless, an April study by another group reported that two newborns whose mothers had SARS-CoV-2 infection late in pregnancy suffered from seizures and brain damage. When one of the infants died at 13 months of age, traces of the virus were found in the brain.
Overall, the virus is believed to cross the placenta infrequently. Most babies born to mothers with COVID-19 do not test positive for COVID-19, said Asma Khalil of St George’s University Hospital in London.
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