Pregnant patients hospitalized with COVID-19 had a lower risk of mortality than those who were not pregnant, a retrospective cohort study found.
The mortality rate was less than 1% for pregnant women who were hospitalized with COVID-19 and viral pneumonia, as compared to 3.5% in the nonpregnant population, reported Beth Pineles, MD, PhD, of the McGovern Medical School at UTHealth in Houston, and colleagues.
The median time from hospital admission to death was 18 days in the pregnant cohort versus 12 days among patients who were not pregnant, they wrote in a brief report in the .
The study also found that in subgroups of patients who were admitted to intensive care or required mechanical ventilation, pregnant COVID-19 patients had lower in-hospital mortality compared to those who were not pregnant.
"It's really suggesting that outcomes among pregnant patients with COVID-19 are not worse than nonpregnant patients, which was previously described," Pineles said in an interview with 51˶.
A prior report published by the CDC found a in pregnant women with COVID-19 illness. Pineles said her group expected to replicate these results, and she was taken aback when their analysis produced the opposite outcome.
But compared to the CDC report, which relied on voluntarily reported data from providers, this study's reliance on electronic hospital discharge data make it unlikely that it missed patients, Pineles added. She also noted that these results are consistent with
"It is surprising that the mortality rate was lower for pregnant individuals than non-pregnant individuals," Torri Metz, MD, a maternal-fetal medicine specialist at the University of Utah School of Medicine in Salt Lake City, told 51˶ in an email.
However, said Metz, who was not involved with the study, the higher likelihood of hospitalization in pregnant individuals -- as well as more underlying medical conditions in the nonpregnant group -- may have influenced the lower mortality rate among pregnant patients.
And she noted that the 0.8% mortality rate among the pregnant group was "still relatively high when we think about other viruses and the risk of death with other complications of pregnancy."
In this study, Pineles and colleagues examined the risk of mortality in pregnant women who were hospitalized with COVID-19. They conducted a retrospective cohort study using the Premier Healthcare Database, an all-payer data source that captures a fifth of all U.S. hospitalizations. They included female patients, ages 15 to 45, who were hospitalized with COVID-19 between April and November 2020. To exclude patients with asymptomatic illness, the researchers only included those with a positive test and a viral pneumonia diagnosis.
The analysis consisted of around 1,000 pregnant patients and 10,000 nonpregnant patients who were hospitalized with COVID-19. Compared to the nonpregnant cohort, pregnant women were younger and more likely to have public insurance. They were also less likely to have comorbidities such as hypertension, chronic pulmonary disease, diabetes, and obesity.
In-hospital death occurred in nine (0.8%) pregnant women and 340 nonpregnant women. Among patients who were admitted to the ICU, mortality was 3.5% in the pregnant cohort (nine of 255), and 14.9% in the nonpregnant group (283 of 1,898). Additionally, of all the patients who required mechanical ventilation, mortality was 8.6% (nine of 105) in pregnant women and 31.4% (294 of 937) in women who were not pregnant.
Of all the pregnant patients who died, eight were non-Hispanic Black or Hispanic. Six of the patients were obese, and seven had at least one comorbid condition. The ages of the pregnant patients who died ranged from 23 to 44.
While this report relied on hospital discharge data and is based on a clearly-defined population, Pineles and colleagues acknowledged that there is still the potential for collider bias because the severity of illness and pregnancy can affect hospitalization rates. They also recognized that this study reported a low number of COVID-19 deaths, and the results may lack adjustment for confounding.
While these results show a lower risk of severe COVID-19 outcomes during pregnancy than previously, Pineles noted that it is important for pregnant women to continue taking precautions to avoid infection.
"We definitely think that vaccination, masking, and social distancing are still important for pregnant women to do," Pineles said. But these results may provide some reassurance to pregnant people during the pandemic, she added.
"Pregnant people are already worried about their own health and the health of their baby, and there's been a lot of uncertainty during the pandemic," she said. "Maybe this [study] will help alleviate some of the stress and anxiety."
Disclosures
Pineles and co-authors disclosed support from the Agency for Healthcare Research and Quality, the Thrasher Research Fund, the Society for Maternal-Fetal Medicine, AMAG Pharmaceuticals, and UTHealth.
Primary Source
Annals of Internal Medicine
Pineles B, et al "In-hospital mortality in a cohort of hospitalized pregnant and nonpregnant patients with COVID-19" Ann Intern Med 2021; DOI: 10.7326/M21-0974.