Pregnant women with COVID-19 may pass the virus to their babies, but how often and when this happens is still unclear. Researchers reviewed studies on how SARS-CoV-2 can be transmitted from infected mothers to their babies. Current data shows limited information on the scale and timing of this transmission, due to differences in testing methods and lack of standardized protocols worldwide. More research is needed to understand the full extent of vertical transmission of SARS-CoV-2 and to establish consistent guidelines for sample collection and testing.