After 11 years of recording and publicly acknowledging preventable mistakes, Minnesota hospitals have developed a rhythm to their annual report on “adverse events.’’

Hand in hand with sobering statistics about fatal falls or surgeries to the wrong body parts, the report gives lengthy descriptions of the solutions underway.

A couple of years ago, a major concern was sponges left inside patients during surgeries, invasive procedures or even childbirths. A concentrated effort by the state’s hospitals reduced that to only one such case last year, according to the latest report, released Thursday.

But this year’s report also contained a rare stumper — a new error category of missteps in the delivery process that caused deaths or severe disabilities to newborns whose births were supposed to be uncomplicated.

Six such deaths were reported last year, by hospitals in Woodbury, Maple Grove, St. Louis Park, Worthington, Bemidji and Virginia. But careful analysis — in the hopes that lessons can be learned and future deaths prevented — has found no smoking gun.

“There was nothing we found that really could have been predicted or [suggested] we could have intervened earlier to keep it from happening,” said Dr. Ed Ehlinger, state health commissioner.

Just figuring out how to track this new adverse event was challenging enough. Deaths might be obvious, but determining when they are linked to the delivery process is another matter.

Hospitals have agreed to assume that all such neonatal deaths or severe injuries are associated with the delivery process, and then work backward and rule out other causes such as hidden complications that hadn’t been identified in ultrasounds and prenatal exams. “You assume it’s associated with labor and delivery unless there’s evidence otherwise,” said Julie Apold, patient safety director for the Minnesota Hospital Association.

With reporting underway, Ehlinger is optimistic about preventing newborn deaths, which are traumatic and indicative of whether doctors and hospitals are doing their jobs.

“Infant mortality,” he said, “is one of the indicators of our overall health system.”