Early in the pandemic, it was clear that people with preexisting conditions were at higher risk of complications and severe disease from COVID-19 infection. Pregnant women, in particular, were noted as potentially high-risk patients; some data suggested COVID-19 infection could increase rates of premature birth and preeclampsia. However, there were, and still are, many questions about how COVID-19 infection in pregnant women affects the overall health of both the mother and the fetus.
In an attempt to better understand how COVID-19 infection affects birth outcomes, researchers have recently conducted a retrospective study looking at women who gave birth following COVID-19 infection and subsequent birth outcomes, including how the trimester in which an infection occurs plays a role.
Published in The Lancet Digital Health, researchers describe a retrospective study of pregnant women at Providence St. Joseph Hospital. Researchers gathered the electronic records and compiled a cohort of individuals who had been COVID-19 positive during their pregnancy. To test against other variables that could affect pregnancy outcomes, researchers also compiled a cohort of individuals who had no positive tests during their pregnancy.
Using this data, researchers gathered information about the COVID-positive cohort, including a range of other details about each participant's health. This data was then used to build a model that could be used to predict “gestational age” when a baby was born in maternal COVID cases. Given that fetuses are generally more susceptible to stress during different points in a pregnancy, researchers suspected that when the infection occurred would impact birth outcomes.
Indeed, researchers found that infections occurring earlier in a pregnancy seemed to pose more negative birth outcomes, including risk of preterm and stillbirth. This could be attributed to higher levels of ACE2, which COVID spike proteins use to enter human cells. As a result, researchers noted that increased monitoring of women with infections during the first and second trimester may be helpful.
They also found that severity did not seem to have any (or at least, minimal) effect on gestational age at delivery.