Asymptomatic SARS-CoV-2 infection is not associated with miscarriage in early pregnancy: a retrospective analysis

The prevalence of SARS-CoV-2 infection during pregnancy is relatively unknown. In this study we report the potential impact of undiagnosed SARS-CoV-2 infection on pregnancy loss in the first half of pregnancy by comparing the prevalence of the infection in a retrospective group of pregnant women with miscarriage (n=62) and a prospective control group with no pregnancy loss in the first trimester (n=218). Of 62 women who had miscarriage, 2 (3.2%) resulted IgM for SARS-CoV-2 negative and IgG seropositive, while of 218 pregnant women, 5 (2.3 %) resulted IgM for negative and IgG seropositive. The SARS-CoV-2 seroprevalence was not significantly different in the two groups of women, therefore excluding a significant role of SARS-CoV-2 infection in pregnancy loss. Therefore, our data show that SARS-CoV-2 infection within the first trimester does not seem to predispose to early pregnancy loss and that the impact of asymptomatic or mildly symptomatic SARS-CoV-2 infection on pregnancy appears limited.