Introduction and objective: The COVID-19 pandemic has significantly impacted the global healthcare system and all aspects of medical education. In this study, the knowledge of parents about the prophylactic use of vitamin K in newborns and infants, and the method of prophylaxis of vitamin K deficiency bleeding was assessed. Materials and methods: Data for the study were collected by conducting an online survey of 232 parents. They were assigned to two groups: group 1, responding before the COVID-19 pandemic, and group 2, responding during the COVID-19 pandemic. Results: Vitamin K was administered intramuscularly in 99% of cases in group 1 and 57% in group 2 (significant relationship – p < 0.001). Half of group 2 mistakenly thought that vitamin K was given orally after childbirth. This answer was given by 20% of people from group 1 (p < 0.001). Conversely, the correct answer (intramuscular injection) was given by 52% of respondents in group 1 and 46% in group 2. More parents in the pre-pandemic group knew the symptoms of vitamin K deficiency in the body (54% vs. 25%; p = 0.006), when compared to the parents surveyed during the pandemic. Almost half of group 2 (46%) and 23% of group 1 also reported that oral vitamin K supplementation is recommended after childbirth (p = 0.001). Conclusions: Based on the study, it can be concluded that parents’ knowledge of the prevention of vitamin K deficiency is low. The COVID-19 pandemic has had an adverse effect on the public awareness and education regarding vitamin K deficiency bleeding prophylaxis commonly used in Poland. There is a link between the emergence of the COVID-19 pandemic and parents’ perspectives on the intramuscular administration of vitamin K for the purpose of preventing deficiency.