Effect of SARS-CoV-2 infection during pregnancy on maternal and perinatal mortality: A systematic review of cohort studies

Aim: The aim of this systematic review was to examine cohort studies investigating the association of this infection with maternal and perinatal mortality, especially stillbirth. Material and Methods: According to the Preferred Reporting Items for Systematic Reviews and Meta -Analyses (PRISMA 2020) guidelines, a search was conducted on 3 databases: PubMed, Scopus and ScienceDirect for cohort studies published up to 24 April 2022 in English or French. Studies comparing the incidence of maternal or perinatal mortality among infected and uninfected pregnant women were retained (PROSPERO registration number: CRD42022341500). Results: Initially, 2818 articles were identified, and 24 cohort studies were included. The overall population was 1511875 pregnant women. Of seventeen studies addressing maternal mortality, six reported a significant increase in death incidence among the exposed group (RR ranging from 13.3 to 22.26). Although, three studies found no significant difference (p >= 0.05). Eight studies reported no maternal deaths, of which 7 were conducted in the first year of the epidemic and 5 in a single center. The association of SARS-CoV-2 infection with perinatal mortality and stillbirth was not significant in 9/17 studies. However, 6/17 studies reported a significant association (RR ranging from 1.2 to 4.7). Factors that may influence outcomes included disease severity, body mass index, ethnicity, previous morbidities, and gestational age at the time of exposure. Discussion: The association between SARS-CoV-2 infection and maternal mortality was contrasting. Single -center studies revealed a low risk, while larger studies indicated a high risk of death. Furthermore, the association with perinatal mortality was less strong.