CHICAGO (AP) -- Doctors failed to notice abuse-related head injuries in toddlers and babies nearly a third of the time in a new study.

They were especially likely to miss such injuries in white children from two-parent homes.

``We all have our particular preconceived notions of what child abuse would look like. But, in fact, it's not a problem that's isolated to children of color or those from single-parent families,'' said Dr. Carole Jenny, a pediatrician who led the study while at Children's Hospital in Denver. She is now a professor of pediatrics at the Brown University.

The study, published in Wednesday's Journal of the American Medical Association, said doctors missed even life-threatening brain hemorrhaging and skull fractures.

Prompted by the case of a brain-damaged child who had visited eight doctors before being correctly diagnosed at the Denver hospital, Jenny and her colleagues reviewed medical charts compiled from 1990 to 1995 for 173 children under age 3 who had been treated by doctors throughout the Rocky Mountain region.

They found that 54 of the children, or 31 percent, had abuse-related injuries that weren't caught for an average of seven days. Five of the children died.

The researchers determined four of those five might have been saved if the abuse had been noticed sooner because they were among 15 children who were injured again after the missed diagnosis.

Kevin Kirkpatrick, a spokesman for the Chicago-based National Committee to Prevent Child Abuse, said that fits with his agency's finding that 41 percent of abused children who died in 1995 through 1997 had been seen by officials from child protective services.

Doctors in the study missed nearly four in 10 abuse-related head injury cases in white children or those from two-parent families, while missing about two in 10 cases in non-white children or those living with a single parent.

``We all need to adjust our mindset,'' Kirkpatrick said.

In an accompanying editorial, Dr. John Leventhal, a professor of pediatrics at Yale University, said it's unlikely doctors will make the correct diagnosis all the time, but ``physicians can do better.''

Jenny recommended developing blood tests to detect enzymes released in the bloodstream when a child is injured through shaking or impact.