Literature search
To ensure that the work was of high quality, this study was performed following the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines[13] (Table S1). English-language publications were comprehensively searched in the Cochrane Library, PubMed, and EMBASE databases from the dates of inception until May 2021. The search terms used were “pregnancy OR mothers OR pregnant OR gestational OR prenatal OR perinatal OR gestation” and “neuraminidase inhibitors OR oseltamivir OR zanamivir.” The reference lists of the retrieved articles were manually examined to identify studies not found in the database search.