Vitamin shot, given at birth, reduces risk of dangerous bleeding
Female newborns may miss out on potentially life-saving vaccines more often than male newborns, according to a study from a Philadelphia health system.
Among babies born at three hospitals affiliated with the University of Pennsylvania, female newborns were less likely to receive vitamin K than male newbornsreport the researchers on June 15 in Open JAMA Network. The apparent reason: Parents cannot have male babies circumcised in hospitals if they refuse the vitamin K injection, which helps prevent bleeding.
The research team at Children’s Hospital of Philadelphia analyzed medical records of more than 93,000 infants born between 2018 and 2025. There was a sharp overall decline in vitamin K intake at birth, which is given unless parents refuse. But the refusals were focused on female newborns, who made up two-thirds of the 777 infants who did not receive the vaccine.
Among female infants, 10 newborns per 1,000 births were not vaccinated in 2018, increasing to 20 per 1,000 in 2025. For male infants, the rate increased from 4 per 1,000 births to 10 per 1,000.
During the study, about three-quarters of newborn males were circumcised in hospital. For parents who would otherwise say no to the vaccine, wanting this procedure appears to tip the scales toward more male than female babies receiving vitamin K. The findings suggest that there may be a need for vitamin K acceptance strategies specific to parents of female babies, the research team notes.
Vitamin K reduces the risk of developing dangerous hemorrhage early in life, which can be fatal. Newborns need a dose because little of the vitamin passes from the placenta to the fetus and breast milk doesn’t provide much either. Universal vitamin K injections for newborns have been the standard in the United States since 1961. But misinformation about the shooting and other routine newborn care contributed to a nationwide increase in parental refusal of vitamin K.
The new study also found a decrease in the number of people receiving the hepatitis B vaccine at birth over time, with 83% of people with vitamin K deficiency also saying no to the vaccine. Earlier this year, a judge halted attempts at federal changes pediatric immunization schedule, including elimination of the birth dose of hepatitis B vaccine. The American Academy of Pediatrics and other medical societies I always recommend this dose.