SARS-COV-2 IgG antibody response in pregnant women at delivery.

BACKGROUND: The prevalence of COVID-19 infection during pregnancy is not known. COVIPREG is a prospective French multicenter study to assess the seroprevalence at the time of delivery and the maternal and neonatal impact of COVID-19 infection during pregnancy. In order to study factors associated with poor outcomes after COVID-19 Infection during pregnancy and adapt the sample size of the study, a preliminary assessment of the prevalence of SARS-CoV-2 IgG was planned after 500 inclusions in a one perinatal center of Paris area. OBJECTIVES: To assess the prevalence of SARS-CoV-2 IgG antibody response in pregnant women at the time of delivery during the COVID-19 pandemia. STUDY DESIGN: A prospective observational study at Cochin hospital (Level III maternity). Patients admitted for delivery were offered to participate to the study. Each patient participating to the study was tested for anti-SARS-CoV-2-IgG antibodies using a commercially available ELISA. RESULTS: Among the 529 patients included in the COVIPREG study between April 29 and June 26, 529 were assessed for SARS-CoV-2 IgG antibody response and 25 had a positive test, ie 4.7% with a confidence interval at 95% [3.0%-6.9%]). CONCLUSIONS: Four months after the beginning of the infection in Paris, the seroprevalence of SARS-CoV-2 IgG in pregnant women at the time of delivery is low. Studies evaluating the impact of COVID-19 infection during pregnancy should take this information in account in order to adapt the sample size.