Sweden's Vitamin K Refusal Surge Linked to Infant Bleeding Cases
A major Swedish study found that rising parental rejection of newborn vitamin K shots correlates with increased bleeding diagnoses in infants—a rare but life-threatening condition. The findings matter to hospitals, insurers, and public health officials as vaccine hesitancy expands beyond traditional immunizations into routine preventive care.
Originaltitel: Vitamin K Prophylaxis in Newborns and Bleeding in Infancy.
Vitamin K-profylax till nyfödda minskar blödningsrisken drastiskt — men allt fler föräldrar vägrar behandlingen. Svenska data från över 2 miljoner födslar mellan 2003 och 2021 visar att andelen nyfödda utan intramuskulär vitamin K steg från 0,66 procent år 2006 till 1,50 procent 2021. Barn utan profylax hade 1,5 gånger högre risk för blödning under första levnadshålvåret och nästan 3 gånger högre risk för intrakraniell blödning jämfört med behandlade barn. Karolinska Institutet genomförde studien med data från svenska medicinska register. För vårdgivare och regionledning innebär detta ett regulatoriskt och kliniskt behov att återkommunicera vitalet i denna profylax — ökningen av vägran motsäger den etablerade evidensen. Tidshorisont för interventioner är omedelbar för att förhindra alvarliga komplikationer.
IMPORTANCE: Vitamin K deficiency bleeding in infants is a rare but potentially life-threatening condition that is effectively prevented by newborn intramuscular vitamin K prophylaxis. Despite this, there are reports of increasing parental refusal of vitamin K prophylaxis globally. OBJECTIVE: To evaluate temporal trends of prophylactic newborn vitamin K administration and its association with bleeding diagnoses during infancy. DESIGN, SETTING, AND PARTICIPANTS: This was a nationwide cohort study of births between January 1, 2003, and December 31, 2021, followed up until 6 months of age. The study setting was in Sweden and included all live-born infants born at 35 or more weeks' gestation during the study period. Data analysis was performed from June 1 to December 19, 2025. EXPOSURE: The exposure was nonreceipt of intramuscular vitamin K administration at birth. MAIN OUTCOMES AND MEASURES: The primary outcome was a bleeding diagnosis within the first 6 months of life. Data from the Swedish Medical Birth Register was linked to multiple Swedish national registers. Logistic regression was used to estimate adjusted odds ratios (aORs) with 95% CIs. RESULTS: Among 2 020 302 live births, 24 089 infants (mean [SD] gestational age, 40.0 [1.6] weeks; 12 472 male [51.8%]) had no record of intramuscular vitamin K administration at birth. The rate of nonreceipt decreased during the first study years from 1.32% (1242 of 94 214 newborns) in 2003 to 0.66% (667 of 100 429 newborns) in 2006, and then gradually increased and more than doubled to 1.50% (1619 of 107 915 newborns) in 2021. Infants without intramuscular vitamin K administration had 1.54-fold higher odds (aOR, 1.52; 95% CI,1.27-1.81) of bleeding and 3.18-fold higher odds (aOR, 2.91; 95% CI, 2.13-3.96) of an intracranial bleeding episode during infancy, compared with infants with intramuscular vitamin K. CONCLUSIONS AND RELEVANCE: This cohort study shows that the number of infants in Sweden who do not receive intramuscular vitamin K administration at birth to prevent bleeding episodes continues to be low but is increasing, and these infants have a significantly higher associated risk of bleeding episodes, including intracranial hemorrhages. These findings suggest the importance of intramuscular vitamin K administration in the newborn period to prevent bleeding episodes and the need for continued education of parents and caregivers on its significance.