A new study is raising concerns about more babies missing their vitamin K shot at birth, as doctors remind parents why the shot matters.

Researchers looked at medical records for about 11 million U.S. infants born at 35 weeks or later from 2017 through 2025. Over that time, the share of newborns who received injectable vitamin K fell from 97.7% to 95%.

Diagnoses of bleeding linked to vitamin K deficiency rose from 24 to about 107 for every 100,000 infants. That is a 347% increase, though the condition was still uncommon. The study did not give separate figures for New Jersey or Lakewood.

Vitamin K helps blood clot. Newborns have low levels of it, and a shot after birth helps protect them from dangerous bleeding, including bleeding in the brain.

“It is crucial for parents to know that the vitamin K injection is not an immunization, but an essential vitamin,” said Dr. Cathleen Ballance, a pediatric hospitalist at K. Hovnanian Children’s Hospital at Jersey Shore University Medical Center, in a Hackensack Meridian Children’s Health release today.

“Skipping this shot leaves a newborn at risk of developing uncontrolled bleeding, which can lead to permanent brain damage or even death,” she said.

Ballance was commenting on the research and was not one of its authors.

The study, published Thursday in JAMA Pediatrics, found that lower use of the shot and more bleeding diagnoses happened over the same period. It does not prove that skipping the shot caused every additional case.

The researchers relied on records from health systems using Epic, so the findings do not include every U.S. baby. Diagnosis codes can be wrong, some brain-bleeding cases may have been missed, and other health problems can also affect a baby’s risk.

For parents preparing for a birth, the findings are a reason to discuss the vitamin K shot with their baby’s doctor and ask questions before delivery.