INTRODUCTION
Routine newborn intramuscular vitamin K prophylaxis has nearly eliminated vitamin K deficiency bleeding in the US since initiation of universal administration in 1961.1 Nonetheless, there are reports of increasing parental vitamin K refusal and resultant bleeding.2 To mitigate risk of such bleeding, newborns require prophylaxis at birth because of minimal vitamin K placental transfer, poor gastrointestinal absorption, and low concentrations in breast milk. Parents sometimes refuse newborn vitamin K administration because of concerns regarding necessity, injection pain, and potential adverse effects.1–3 Public skepticism regarding pediatric preventive interventions has grown after the COVID-19 pandemic.4 Whether national rates of intramuscular vitamin K administration have changed in this period is unknown. This study aimed to evaluate whether the proportion of newborns not receiving intramuscular vitamin K has increased in recent years and identify factors associated with nonreceipt.