IDAHO — Half of the newborns seen by Dr. Tom Patterson on one day at an Idaho hospital did not receive vitamin K shots. More than a quarter of the newborns seen by Patterson on another recent day at the hospital also did not receive the vitamin K shot.

Some parents decline preventive measures like vitamin K injections and eye ointment for newborns because they fear they might cause problems and do not want the newborns to feel pain. Parents who decline vitamin K shots are more likely to also refuse hepatitis B vaccination and erythromycin eye ointment for their newborns.

The Idaho chapter of the American Academy of Pediatrics reported eight deaths from vitamin K deficiency bleeding in Idaho over the preceding 13 months at a February meeting. Refusals of vitamin K shots among newborns in the United States rose from 2.9% in 2017 to 5.2% in 2024 based on an analysis of more than 5 million births nationwide.

"But I hear from families that it's hard to make decisions right now because they're hearing conflicting information," said Kelly Wade, a neonatologist. Social media posts question doctors' advice on measures such as vitamin K injections and erythromycin eye ointment for newborns.

Doctors warn that babies cannot absorb unregulated vitamin K drops promoted on social media. Some parents agree to a vitamin K shot when they learn it is not a vaccine.

"The child essentially had a stroke as a newborn and wound up with severe developmental delays and ongoing seizures," said David Hill, a pediatrician and researcher. Newborns who do not receive a vitamin K shot are 81 times more likely to develop severe bleeding than those who do.

Babies are born with low levels of vitamin K and cannot produce enough intestinal vitamin K until around six months of age when they begin eating solid foods. Vitamin K is important for helping blood clot and preventing dangerous bleeding in babies, such as bleeding into the brain. Before vitamin K injections became routine, about 1 in 60 babies experienced vitamin K deficiency bleeding.

"There's more mistrust from the conservative side, but there's plenty on the more liberal side as well," said Steven Abelowitz, a pediatrician. "Then there's a ton of misinformation."

Dr. Heather Felton has observed that most families decide to get the vitamin K shot and that she has seen no increase in refusals. Rates of hepatitis B vaccination at birth have declined in recent years.