COVID-19 infection in pregnancy increases risk of hospitalization, preterm birth: national study

Canada’s first national peer-reviewed study on COVID-19 in pregnancy found becoming infected while expecting increases the risk of requiring hospitalization or intensive care, and of giving birth early. 

Researchers with the CANCOVID-Preg program analyzed outcomes from 6012 cases of COVID-19 in pregnancy from March 2020 to the end of October 2021, and compared the results with others who were not pregnant and with pregnant people who did not contract the virus. 

Out of those cases, 466 (7.75 per cent) required hospitalization and 121 (2.01 per cent) were admitted to an intensive care unit (ICU). 

UBC obstetrics and gynaecology professor Dr. Deborah Money, who is leading the national research project, said when you compare those numbers to non-pregnant women of the same age, they are substantially higher rates.

“About three-fold higher rates of hospitalization, and over five-fold higher rates of intensive care unit admission,” she said. “There were other factors that we found that made the risk of complications higher: the older the woman was, the further along in her pregnancy, if he had pre-existing high blood pressure or diabetes.” 

Money said they also saw a “disproportionate” level of COVID-19 infection and complications in non-white individuals. 

The study also found an increased risk of preterm birth, even for mild COVID-19 cases, with a rate of 11.1 per cent in affected pregnancies, compared to 6.8 per cent among those that were unaffected. 

“We are seeing almost double the rate of preterm birth,” Money said. “I think people don’t appreciate that is actually a significant risk factor for infants health and may impact them long term.” 

Money added none of the patients examined by the study who had serious outcomes such as hospitalization and ICU admission had been double-vaccinated. 

“We did see a real difference with vaccine versus not vaccine,” she said.  “And just reinforcing the value of vaccine, not in the prevention of infection, but in the prevention of serious outcome.” 

Money said she hoped the findings provide even more motivation for those who are pregnant to get vaccinated if they haven’t already. With the pandemic in its sixth wave in Canada, and with the fewest health restrictions in effect since the beginning of the pandemic, she also advised pregnant people to continue to take precautions. 

“We would be very much encouraging pregnant women to take a booster if it’s their time,” she said. “I think it’s important as we sort of try to go to a new normal that we don’t trivialize a COVID infection in pregnancy, particularly if the person is un(vaccinated) or partly vaccinated.” 

In the months before Danica Miscisco of Maple Ridge gave birth to her daughter Maisy last June, she got her first of three COVID-19 vaccines soon after the shot was prioritized for pregnancy in B.C.

“There were so many people, and still now, getting hospitalized who aren’t vaccinated,” she said. “So just the risk of that being a possibility for me was very scary.”

Miscisco said she’s glad she decided to get vaccinated when she did, and is still taking precautions, as her little girl is too young at this point to do the same.

“Being able to get vaccinated, I was so less stressed out,” she said. “I’m really hoping pregnant people continue to get the vaccine if they haven’t already…and I really want to stress people getting their booster shot as well.

"Just because the mandates are over, it is still going on, and you’re not just affecting yourself, you’re affecting people around you. At least do it for the people who are at risk.”

The findings were published Monday in the Journal of the American Medical Association.