Federal officials identified a cluster of newborns in Tennessee with late vitamin K deficiency bleeding, a serious but preventable bleeding disorder.

Preliminary findings of the investigation of the Centers for Disease Control and Prevention in Atlanta, in collaboration with the Tennessee Department of Health, found from February and September four cases of late VKDB were diagnosed at a hospital in Nashville -- three of the infants had bleeding within the brain and the fourth had gastrointestinal bleeding. None of the infants received a vitamin K injection at birth, officials at the CDC said.

The CDC's Morbidity and Mortality Weekly Report said in each case, the newborn's parents declined vitamin K injection at birth, mainly because they were unaware of the health benefits of vitamin K for newborns.

In the United States, a vitamin K injection at birth has been a standard practice since it was first recommended by the American Academy of Pediatrics in 1961. A dose of vitamin K at birth prevents VKDB, the CDC said.

The late form of VKDB can develop in infants two weeks to six months of age who did not receive the vitamin K injection at birth and do not have enough vitamin K dependent proteins in their bodies to allow normal blood clotting, officials said.

Untreated, this can cause bleeding in the brain, which may lead to neurological problems and can even be fatal. The risk for developing late VKDB has been estimated at 81 times greater among infants who do not receive a vitamin K injection at birth than in infants who do receive it, the CDC said.

"Not giving vitamin K at birth is an emerging trend that can have devastating outcomes for infants and their families," Dr. Tom Frieden, director of the CDC, said in a statement. "Ensuring that every newborn receives a Vitamin K injection at birth is critical to protect infants."

The CDC and the Tennessee Department of Health are still investigating if other cases of late VKDB occurred in the state in recent years.

"Fortunately all of the infants survived," said Dr. Lauren Marcewicz of the CDC's National Center on Birth Defects and Developmental Disabilities. "It is important for health professionals to educate parents about the health benefits of vitamin K at birth."