MONTREAL -- New data from a Canadian study links COVID-19 to increased risk of pregnancy complications including preterm birth and stillbirth, with the risks rising if infection is severe.
Montreal researchers conducted a meta-analysis of 42 studies involving 438,548 pregnant people around the world.
Authors including Dr. Nathalie Auger of the University of Montreal's School of Public Health said the data "provides clear evidence that symptomatic or severe COVID-19 is associated with a considerable risk of preeclampsia, preterm birth and low birth weight."
"Clinicians should be aware of these adverse outcomes when managing pregnancies affected by COVID-19 and adopt effective strategies to prevent or reduce risks to patients and fetuses," concludes the study, published Friday in the Canadian Medical Association Journal.
The study says COVID-19 patients were more likely than those without the disease to experience stillbirth, preterm birth and preeclampsia, a condition that causes high blood pressure in the second trimester of a pregnancy.
Compared with asymptomatic patients, symptomatic patients were at double the risk of preterm birth and a 50 per cent increased risk of caesarean delivery.
Meanwhile, those with severe COVID-19 had a fourfold higher risk than those with a mild case to experience high blood pressure and preterm birth.
The reason for increased risk was unclear, but researchers said it could be because the virus that causes COVID-19 stimulates an inflammatory response affecting blood vessels.
"Lack of knowledge about SARS-CoV-2 infection in pregnancy has raised urgent questions among obstetricians and neonatologists about the risk of maternal, fetal and neonatal morbidity and mortality," the study says.
"There is an urgent need for evidence to guide clinical decisions."
Dr. Deborah Money, an obstetrician who is leading a national surveillance project on pregnancy during the pandemic, said findings about preeclampsia in the newly published study are surprising.
"They've given some suggestions related to the information associated with getting COVID-19 that may be affecting the placenta, but I think (with) one meta-analysis among the entire body of international literature that is different, we should probably just take it with a grain of salt," said Money, a professor in the University of British Columbia's department of obstetrics and gynecology.
"We so far have analyzed 1,800 cases of COVID in pregnancy in Canada, so we're all scanning and watching and looking for any adverse outcomes that we weren't necessarily expecting because of this rather unusual infection and reacting to those that we think are solid and robust," she said of obstetricians and gynecologists around the world.
Findings from Canada have already shown pregnant women with COVID-19 are at higher risk of hospitalization and preterm birth while data so far has not shown whether stillbirths are statistically higher.
Money said she found some aspects of the Montreal study problematic because it includes women with both suspected and proven COVID-19 infections. It's also based on a diverse group of international studies involving parts of the world that have challenges providing prenatal care, which would have different baseline rates of pregnancy outcomes.
"We are seeing some disturbing literature from Mexico and South America, which we think is related to social determinants of care and access to health care," she said.
Pregnant women should take all precautions to reduce interactions outside of their family bubble and consider getting vaccinated, Money said.
"The message I want to send is it's very important that women access health care as needed. And don't be frightened of doing that because the pandemic is ongoing" Money said, adding conditions such as high blood pressure would be picked up at clinics and hospitals that are taking public health precautions to protect patients.
This report by The Canadian Press was first published March 19, 2021.
