Marna Borgstrom announced Wednesday she is retiring as CEO of Yale New Haven Health in March and her successor will be Chris O'Connor, who became president of the health care system in October.

During her time as CEO, Smilow Cancer Hospital opened, Northeast Medical Group was created, and Lawrence + Memorial and Westerly hospitals affiliated with the health care system.

Borgstrom began her career at Yale New Haven Hospital as an administrative fellow in 1979 and became the first female CEO of Yale New Haven Health in 2005.

She said that 43 years ago, newly married and fresh out of graduate school, she told her husband they'd stay for a year or two and then go back to the San Francisco Bay Area. She hasn't kept that promise.

"Every time I had an opportunity to look at something elsewhere, I had even greater opportunities at Yale New Haven Hospital, growing the Yale New Haven Health system," Borgstrom said. But she said "there is a time for leadership changes in every organization, and that time is coming up for me."

She said the coronavirus pandemic didn't play a role in her decision to retire at this point, and if anything, it "delayed this a little bit, because with so much unknown going on, we did not want to do anything that could destabilize the organization in a very delicate time."

Borgstrom said she has been planning for her retirement with the board of trustees, which decided Wednesday morning to accept her retirement proposal and offer the position to O'Connor.

"She has brought an unmistakable blend of commitment and vision throughout her career, and most especially as the chief executive officer of this organization since 2005," Board Chairman Vince Calarco said in a news release. "In so many ways, Marna has come to define the very essence of Yale New Haven Health."

Yale University President Peter Salovey said Borgstrom "has fostered vital collaborations with the Yale School of Medicine to improve patient care and advance medical and clinical research."

Gov. Ned Lamont said Borgstrom has been a partner since day one of the pandemic, offering balanced and thoughtful input.

Awards she has received include the American Hospital Association Grassroots Champion Award, the Anti-Defamation League Torch of Liberty Award, and the Greater New Haven Chamber of Commerce Community Leadership Award. She serves on the boards of the Connecticut Hospital Association and New Haven Promise.

O'Connor, who called it "very humbling" to be named to this position, said the two will work together to ensure that when Borgstrom's retirement comes in March, it will be a seamless transition.

O'Connor served as executive vice president and chief operating officer of Yale New Haven Health from 2012 to 2020, the position Borgstrom held from 1994 to 2005.

Prior to joining Yale New Haven Health in 2012, O'Connor served as president and CEO of the Hospital of Saint Raphael, which integrated into Yale New Haven Hospital in 2012. Before that, he served as president of Caritas St. Elizabeth's Medical Center in Boston and vice president of clinical operations for Ochsner Clinic Foundation in New Orleans.

O'Connor has master's and bachelor's degrees in hospital administration from George Washington University. He is vice chairman of the Connecticut Hospital Association Board, and serves on the boards of Northeast Medical Group and Greenwich Hospital.

Going forward, a challenge for Yale New Haven Health — as with other organizations — will be developing and maintaining its workforce.

"We are concerned about nursing supply," Borgstrom said, adding there are "a lot of people who are completely burned out after COVID who want to work fewer hours." She said the health care system must also continue to reengineer the work, "because simply looking for the bodies to backfill, the way we've always done things, I don't think is going to be successful."

e.moser@theday.com