Vitamin K deficiency bleeding: newborn shot refusals double, US studies find

Two large US studies published on Thursday, 5 November 2026 found that more parents are declining the vitamin K injection routinely given to newborns, and that vitamin K deficiency bleeding in infants has risen sharply over the same years. A study in the journal JAMA, led by researchers at Children's Hospital of Philadelphia, followed more than 5.2 million infants and found that the share of newborns who did not receive the shot more than doubled, from 3.1% in 2017 to 6.8% in 2025. A companion research letter in JAMA Pediatrics, from a team at Children's Hospital of Richmond at VCU, used records of more than 11 million infants and found that diagnoses of vitamin K deficiency bleeding rose from 24.0 to 107.4 per 100,000 infants between 2017 and 2025.

Vitamin K is needed for blood to clot, and the injection given shortly after birth is meant to prevent vitamin K deficiency bleeding, which in its most serious form can mean bleeding inside a baby's skull. The new studies are among the largest to measure how often families now decline that injection, and what has happened to bleeding rates as they do.

According to reporting on the studies, parents who declined the shot most often cited worries about the pain of the injection, possible side effects and doubts that it is needed. The researchers have also noted gaps in the data: births at home and in birth centres, where refusals are thought to be highest, are largely missing from hospital records, and the US Centers for Disease Control and Prevention does not track refusals or bleeding nationally.

For families, the studies are a reminder that decisions taken in the first hours of a baby's life are often made quickly, in a tired and emotional moment, and that the evidence behind routine newborn care is worth discussing with the doctor or midwife well before the birth. The research does not give individual advice; it describes risks across millions of births.

Peepals calculation: the share of newborns not given the shot rose about 2.2 times (6.8 ÷ 3.1 ≈ 2.19), while diagnosed vitamin K deficiency bleeding rose about 4.5 times (107.4 ÷ 24.0 ≈ 4.48, the reported 347% increase). Among infants without the shot, bleeding inside the skull was about 2.5 times as common (33 ÷ 13 ≈ 2.54), and the crude difference in any bleeding event was one extra case per 100 infants (2.9% against 1.9%). Our calculation from the reported figures.

Short-term: The studies give paediatricians, midwives and hospitals in the United States fresh national numbers to use when parents ask about the newborn injection. An accompanying JAMA editorial focused on how doctors communicate the risk of declining it.

Long-term: The data gaps the researchers describe, especially for home and birth-centre births and the lack of national tracking, mean the full picture is not yet known; how refusal rates move in the coming years will be watched closely by doctors.

Who is affected: Newborns and their parents, especially families who plan home or birth-centre deliveries; paediatricians, obstetricians, midwives and nurses who discuss the injection before and after birth; and public health agencies.

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