There are at least 3 different sources of data on births and/or deliveries in Poland, namely the National Health Fund, the Department of Screening Tests and Metabolic Diagnostics at the Institute of Mother and Child, and Statistics Poland (formerly the Central Statistical Office). Even though they contain complementary data, it is not possible to obtain comprehensive statistics based on any of the sources alone, while combining them is not obvious. Although this is possible for the first 2 sources – and only to a limited extent (as individual data are reported according to the mother’s identifiers), the statistical data from Statistics Poland are available in aggregated form only. Moreover, even after combining the data from the National Health Fund and the Department of Screening Tests and Metabolic Diagnostics at the Institute of Mother and Child and, hence, the acquisition of more comprehensive information on mothers and their newborns, these newborns are still not uniquely identifiable as they lack personal identification numbers, e.g., the Polish national identification number (PESEL). As a result, the statistics prepared for this paper are based on the estimated number of delivered newborns. Also, the data are not without certain flaws and errors because they are reported ambiguously, while labour and delivery data are not available for every single birth.