Supplementary Material for: First-trimester SARS-CoV-2 infection: clinical presentation, inflammatory markers and obstetric outcomes

Objective: Second and third trimester SARS-CoV-2 infections may have an increased risk of obstetric complications. However, data on first-trimester infections are scarce. We sought to characterize the clinical and inflammatory presentation, and pregnancy outcomes of first-trimester infections. Methods: A population-based multicenter study including 817 singleton pregnancies with SARS-CoV-2 serologic testing at 8-14 weeks between March and May 2020. Blood count, uterine artery Doppler and pregnancy-associated plasma protein A (PAPP-A) were performed in all women. Placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), IL-6 and ferritin were determined in positive women. Obstetric outcomes were evaluated. Results: The prevalence of first-trimester infection was 15.2% (n=124). 72.6% of positive women were asymptomatic. Symptomatic women had higher rates of lymphopenia (1.91x109/L vs 2.16x109/L, P=0.017), and increased levels of IL-6 (9.1% vs 1.2%, P=0.051), but lower rates of decreased ferritin (6.3% vs 19.8%, P=0.015). PAPP-A was higher in symptomatic women compared with asymptomatic and negative women (1.44 (IQR 0.90-1.82) vs 1.08 (IQR 0.66-1.61) P=0.014, vs 1.08 (IQR 0.77-1.55) P=0.019, respectively). Obstetric outcomes were not increased. Conclusions: First-trimester SARS-CoV-2 infections are mostly asymptomatic, with a mild increase of inflammatory markers in symptomatic women. Obstetric complications were not increased, but PAPP-A levels were higher in symptomatic women.