A study led by researchers from the University of Washington Schools of Medicine and Public Health found that the coronavirus disease 2019 (COVID-19) can severely affect pregnant women who were considered overweight or obese before they became pregnant.
Findings from the study, published May 15 in the American Journal of Obstetrics and Gynecology, show that women who have COVID-19 face a higher incidence of severe pneumonia, which could lead to preterm birth. The findings also suggest that obesity may heighten a woman's risk for this and other COVID-related symptoms during pregnancy.
Erica Lokken, an epidemiologist and post-doctoral fellow in the Department of Global Health at the UW Schools of Public Health and Medicine, was lead author of the paper. Kristina Adams Waldorf, a professor of obstetrics and gynecology at the UW School of Medicine and adjunct professor in the global health department, was the study's senior author.
“One of the most important study findings is that in nearly all cases of severe COVID-19 disease, women were either overweight or obese prior to pregnancy and had other conditions like asthma and high blood pressure,” said Adams Waldorf. "The combination of pregnancy, obesity, asthma and a COVID-19 pneumonia can synergistically increase the burden on her lungs.”
According to Adams Waldorf, the effects of COVID-19 in pregnant women is not well understood. To learn more about the potential risks, researchers examined 46 pregnant mothers at 16 hospitals across Washington state who had contracted COVID-19 between Jan. 21 and April 17. Patients involved in the study had been screened for COVID-19 because they developed symptoms during this time period.
“We want to determine the risks of COVID-19 in pregnancy and which subgroups of pregnant women might be at greatest risk," she said. "The next step is to translate this information into public health action so that we can provide information to high-risk pregnant women in communities with higher rates of transmission."
The researchers found that 1 in 7 pregnant women was hospitalized for respiratory concerns and 1 in 8 had a severe COVID-19 pneumonia. For 25% of the women, the effects of COVID-19 on lung function influenced the timing of delivery, and even resulted in a preterm birth in one of the cases.
Furthermore, 93.5% of the women studied experienced some symptoms. About 15% of the women were hospitalized and one was admitted to the ICU. Six of the seven patients hospitalized experienced severe COVID-19 symptoms. Eight deliveries occurred in the group during the study. One preterm birth occurred at 33 weeks, and there was one stillbirth, though it was unknown whether this was caused by the coronavirus.
“These findings support categorizing pregnant patients as a higher risk group, particularly with obesity and chronic diseases like asthma and high blood pressure,” the report concluded.
“It is encouraging that most pregnant patients with COVID-19 experienced mild disease, but we cannot discount that one in eight pregnant patients were hospitalized for respiratory concerns," said Lokken, who graduated with an MS and a PhD in epidemiology from the UW School of Public Health. “We have a lot more to learn."
This is the first study published by the Washington State COVID-19 in Pregnancy Collaborative, a group of obstetricians across hospital systems that facilitate 40% of births in Washington state.