Pregnant women with symptomatic COVID-19 are at an increased risk of poorer outcomes, which may include pre-term birth, according to a pair of studies published in The Journal of Maternal-Fetal & Neonatal Medicine and the American Journal of Obstetrics and Gynecology.1,2 The investigators found that the rate of preterm birth in pregnant women who tested positive for SARS-CoV-2 was a function of the severity of infection.1
“The more severe the SARS-CoV-2 infection, the greater the risk of preterm birth," said Roberto Romero, MD, DMedSci, chief of the Perinatology Research Branch and professor of Molecular Obstetrics and Genetics at the Wayne State University School of Medicine, in a press release. "There was a dose-dependent relationship between the severity of SARS-CoV-2 infection and the risk of prematurity.”1
The investigators reported that the excess rate of premature birth was largely due to medically induced preterm birth, initiated due to concerns for the health of the mother. These concerns included preeclampsia, a sudden increase in blood pressure after the 20th week of pregnancy. The condition results in 76,000 maternal deaths and more than 500,000 infant deaths per year.1
“The principal finding is that there is a dose-response relationship between the severity of SARS-CoV-2 infection and the risk of subsequent development of preeclampsia and preterm birth," Romero said in the release. "Patients with severe COVID-19 have a 5-fold greater risk of preeclampsia than asymptomatic patients. Moreover, the relative risk of developing preeclampsia in women with moderate or severe COVID-19 was 3.3-fold higher than in those with asymptomatic or mild infection.”1
A similar study, evaluating 2471 women in the third trimester of their pregnancy, found that there were significantly higher rates of gestational diabetes, lower white blood cell counts, and heavier bleeding during delivery for patients with symptomatic COVID-19. Further, respiratory complications were witnessed in the babies of these patients. They did not, however, encounter any association between COVID-19 and preterm delivery.2
“Our analysis finds there were no significant increase in cesarean delivery in women, who were COVID-19 positive and the incidence of preterm deliveries was not significantly different among the three groups (healthy, COVID positive asymptomatic, COVID positive symptomatic),” said Dr Elior Eliasi in a press release. “Most pregnancy and delivery outcomes were similar between COVID-19-positive and -negative parturients.”2
On average, the increased risk of adverse outcomes was 13.8% higher for patients with asymptomatic COVID-19 and 19.6% higher for those who were symptomatic.
“More data is now needed to better delineate the differences between pregnancy outcomes seen in certain populations, potentially related to different viral characteristics (subtypes, viral load), patient epigenetics, or other factors,” the authors said in a prepared statement. “Additionally, the effects of maternal infection on the fetus both in terms of symptomatic maternal illness and vertical viral transmission remain to be further investigated.”