Pregnant women who contract the virus that causes COVID-19 are nearly 40% more likely to develop serious complications or die during pregnancy compared to pregnant women who don't contract the coronavirus, a new study led by a Utah researcher suggests.
The report, led by Dr. Torri Metz, associate professor of obstetrics and gynecology at the University of Utah and vice chair of research of obstetrics and gynecology at U. Health, was published Monday in the Journal of the American Medical Association. The study also found an increased risk for preterm birth and intensive care unit admissions in newborns.
"We did see that, overall, we saw this increased risk among patients who got SARS-CoV-2 in pregnancy, so I think we can say what we've been saying always — certainly, people should avoid getting SARS-CoV-2 in pregnancy, or any time really," she said during a briefing with media Monday.
"The most important thing about this study is really (it expands) what we knew about complications in pregnancy, related to SARS-CoV-2 infection," she continued, pointing out that the new study finds there are more serious outcomes connected to COVID-19 from common pregnancy complications that were previously unreported.
The results were based on a review of 14,104 patients at 17 different U.S. hospitals between March 1, 2020, and Dec. 31, 2020 — meaning all data is based on the original SARS-CoV-2 strain, not the delta or omicron variants that have each risen globally since the end of 2020. Of that large cluster, only 2,352 pregnant women contracted COVID-19 during that time span.
A team of researchers from various institutions across the country analyzed outcomes of patients who had contracted COVID-19 either during pregnancy or during an immediate postpartum period versus patients who hadn't, Metz said. They also looked deeper into subgroups between people who contracted COVID-19.
She said the team was mostly focused on serious morbidity and mortality, such as maternal death or serious complications from "common things during pregnancy" like high blood pressure, postpartum hemorrhaging or other infections that aren't COVID-19 related.
"Meaning, if somebody had a postpartum hemorrhage, did they then go on to need surgical intervention, radiologic treatment or other higher-level interventions ultimately because that disease progressed into something that was more serious than we typically see?" she explained, adding those types of complications occur in 10-20% of all pregnancies.
Previous research, including work conducted by Metz, indicated pregnant women who contract COVID-19 are more likely to suffer serious effects, such as death or admission to an intensive care unit.
She was the lead researcher for a study presented at a Society for Maternal-Fetal Medicine meeting in early 2021 that found women with more severe COVID-19 symptoms were at higher risk for complications or death than women with no symptoms, or mild or moderate symptoms. But that study was much smaller. It only focused on information from 1,200 pregnant women at 33 hospitals across 14 states from March 1, 2020, through July 31, 2020.
Despite that previous research, Metz said she was a little surprised by the information from a larger field of data in the new study.
The biggest difference is that the new study dove more into common complications beyond COVID-19, like high blood pressure or postpartum hemorrhaging, compared to previous research. COVID-19's impact on those complications is something that hadn't been linked before. It also found women with moderate or worse COVID-19 symptoms were most likely to deal with more serious pregnancy complications.
"I think what this study adds is even when we look at things that are common in pregnancy ... that the people who have SARS-CoV-2 really are at an increased risk of having those common complications progress to something more, that can be life-threatening or really serious morbidity," Metz said.
It's still unclear exactly why SARS-CoV-2 has this effect on pregnant women. The study lists the timing of infections as one of its limitations. About 80% of the infections occurred during the third trimester among the pregnant women studied, which researchers said made it difficult to evaluate the effects the virus has in early pregnancy.
They have some theories. The coronavirus can impact the placenta, which causes "downstream consequences" or it's possible that there's a delay in pregnant women seeking medical help after getting infected, Metz said.
She says future studies could look to find that exact link. Future studies can also dive more into long-term health effects, vaccination status and pregnancy outcomes, as well as any changes based on SARS-CoV-2 variants.
In the meantime, she contends that the results continue to show pregnant women should receive care to ensure they don't develop mild or serious COVID-19 cases. It's why she recommends pregnant women seek medications medically proven to reduce the severity of a COVID-19 infection.
The Utah Department of Health amended its COVID-19 hospitalization risk assessment last month, which dropped pregnancy as an automatic hospitalization qualifier after it was determined to not be among the highest risks. It's not known if the study published Monday will change that position in any way.
Metz also recommends that pregnant women get a COVID-19 vaccine to help avoid mild or serious infections.
"I think this is more evidence to support that we really do want pregnant patients to get vaccinated," she said, "(and) we really do want pregnant patients to get treatments to prevent progression to higher disease severity."