Effect of SARS-CoV-2 infection on perinatal outcomes by disease severity and trimester of pregnancy : A prospective cohort study

Introduction: To describe the effects of maternal COVID-19 on the incidence of small for gestational age (SGA) newborns and other pregnancy outcomes according to disease severity and trimester of infection. Material and Methods: This was a prospective cohort study conducted at Vall d'Hebron University Hospital between March 2020 and June 2023 which included 404 consecutive single pregnancies with SARS-CoV-2 infection classified by severity and trimester of infection and a reference group of 404 consecutive single pregnancies with no suspicion of SARS-CoV-2 infection. The primary outcome was the incidence of SGA newborns. Secondary outcomes included other adverse perinatal and neonatal outcomes. Results: The rate of SGA newborns was higher in the COVID-19 group, with an adjusted relative risk of 1.60 (95 % CI, 1.03-2.48). The risk was particularly elevated in severe cases and when infection occurred during the first trimester. No association was found between COVID-19 and preeclampsia or spontaneous preterm birth. COVID-19 cases showed a higher risk of iatrogenic preterm birth and maternal intensive care unit admission, particularly in severe cases during the third trimester. When analysed by severity and trimester, adverse neonatal outcomes were more frequent in severe cases and in third trimester. Discussion: Pregnancies affected by COVID-19, especially severe cases and first-trimester infections, were associated with a 60 % increased risk of small for gestational age newborns and also raises the risk of iatrogenic preterm delivery, adverse neonatal outcomes, and maternal intensive care unit admission, particularly in severe cases or third-trimester infections. Conclusion: Healthcare providers should remain vigilant about the risk of adverse pregnancy outcomes in severe cases of COVID19.