The "scar" of a pandemic: Cumulative incidence of COVID-19 during the first trimester of pregnancy.

Congenitally- or perinatally-acquired viral infections can be harmful to the fetus but data are limited about prevalence and outcomes of coronavirus disease 2019 (COVID-19) disease during the first trimester of pregnancy. We report epidemiologic data from a study investigating a cohort of women who became pregnant just before or during the COVID-19 pandemic. We recruited 138 consecutive pregnant women attending for first trimester screening (11-13 weeks of gestation) at Sant'Anna Hospital, Turin, Piedmont, Italy, during the plateau and the falling phase of the COVID-19 epidemic curve. Patients were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin M/immunoglobulin G antibody levels and SARS-CoV-2 detection in sera and nasopharyngeal swab samples. COVID-19 cumulative incidence during the first trimester was of 10.1% with high prevalence of asymptomatic patients (42.8%). Similar to the course of the disease in non pregnant adults, 80% to 90% of infections were not severe.The prevalence of reported symptoms was four-fold higher in SARS-CoV-2 positive patients (57%) than in those negative (13%) (P < .001), suggesting that direct self-testing should open doors to confirmatory testing for COVID-19. Our findings support the need for COVID-19 screening in early pregnancy in epidemic areas to plan materno-fetal health surveillance programs.