Variability in COVID-19 symptom presentation during pregnancy and its impact on maternal and infant outcomes across the pandemic

BACKGROUND: With the dominance of different SARS-CoV-2 variants, the severity of COVID-19 has evolved. We aimed to investigate the difference in symptom prevalence and the association between symptoms and adverse pregnancy outcomes during the dominance of Wild-type/Alpha, Delta, and Omicron. METHODS: COVID-19 related symptom prevalence, maternal and specific neonatal outcomes of 5431 pregnant women registered in this prospective study were compared considering the dominant virus variant. Logistic regression models analyzed the association between specific symptoms and intensive care unit (ICU) admission or preterm birth. RESULTS: Infection with the Delta variant led to an increase in the symptom burden compared to the Wild-type/Alpha variant and the highest risk for respiratory tract symptoms, feeling of sickness, headache, and dizziness/drowsiness. An infection with the Omicron variant was associated with the lowest risk of dyspnea and changes in smell/taste but the highest risk for nasal obstruction, expectoration, headaches, myalgia, and fatigue compared to the Wild-type/Alpha and Delta variant dominant periods. With the progression of the Wild-type/Alpha to the Delta variant neonatal outcomes worsened. Dyspnea and fever were strong predictors for maternal ICU admission and preterm birth independent of vaccination status or trimester of infection onset. CONCLUSION: The symptom burden increased during the Delta period and was associated with worse pregnancy outcomes than in the Wild-type/Alpha area. During the Omicron dominance there still was a high prevalence of less severe symptoms. Dyspnea and fever can predict a severe maternal illness.