In 2019, the American Academy of Pediatrics made public education about intramuscular vitamin K administration at birth a public health priority, partly in response to reports of refusal of intramuscular vitamin K by parents of newborns that led to vitamin K deficiency bleeding (VKDB). We reviewed the literature on the frequency of, reported reasons for, and factors associated with refusal of intramuscular vitamin K, incidence of VKDB in newborns who did not receive intramuscular vitamin K, and use of oral vitamin K to prevent VKDB. Without prophylaxis, estimates of the incidence per 100 000 births of VKDB range from 250 to 1700 for early VKDB and from 10.5 to 80 for late VKDB. The frequency of refusal of intramuscular vitamin K by parents ranged from 0% to 3.2% in US hospitals, up to 14.5% in home births, and up to 31.0% in birthing centers. Reported reasons for refusal were concern of harm from the injection, a desire to be natural, and a belief in alternative methods of prophylaxis. Parents who refused intramuscular vitamin K were more likely to refuse immunizations. Many different regimens were used for orally administered vitamin K; it is not clear which is best, but all are less effective than intramuscular vitamin K. VKDB is rare but can result in either neurologic sequelae or death. In addition to continued surveillance of the frequency of both refusal of intramuscular vitamin K and VKDB, a renewed focus on education of and collaboration with parents is needed to address this major public health threat.