Past evidence on fertility responses to external shocks, including economic recessions and outbreaks of infectious diseases, shows that people often put their childbearing plans on hold in uncertain times. The outbreak of the COVID-19 pandemic influenced a wide spectrum of everyday life, from employment, financial wellbeing, uncertainty and health concerns, to work and family reconciliation, dating, marrying, and family planning, thus we may expect certain effect on fertility rates too. The possible impact of the COVID19 pandemic on the birth aggregate during 2021 in Serbia will be calculated based on three different methodologies: Bertillon Birth Effect methodology (BBE), Kearney and Levine (2020) methodology, and Pandemic Wave Impact methodology (PWI - as a newly proposed methodology approach). The primary aim of the paper is to show a potential range of influence of the COVID-19 pandemic on the total number of live births in Serbia during 2021, and the secondary aim is to test our presumptions that this impact mustn't always be negative and that the impact of the pandemic is weakening during the lifespan of the outbreak.