Dr. Sherman Elias, the top obstetrician at Northwestern Memorial Hospital’s Prentice Women’s Hospital, is resigning.

Elias, Chairman of the Department of Obstetrics and Gynecology at Northwestern University’s Feinberg School of Medicine, will resign at the end of the year after seven years, the medical school confirmed to the Tribune.

Elias’ departure is viewed as a surprise, according to sources inside the hospital and medical school. He could not be reached Friday evening for comment.

Elias was influential in the concept and plan behind the new Prentice Women’s Hospital, a $500 million facility that opened three years ago. The hospital provides maternity care for more than 10,000 women and their newborns each year and was designed to treat women at all stages of their lives with inpatient and outpatient services for a variety of services.

“Under Dr. Elias’ leadership, the stature of the Department has risen nationally and internationally,” an internal announcement from medical school dean Larry Jameson said. “He also expanded the clinical and educational missions of the department, creating new divisions and fellowship programs, overseeing the transition to the new Prentice Women’s Hospital, and developing new training opportunities at Stroger Cook County Hospital.”

Jameson said a national search for Elias’ replacement “will begin soon.”