A major OB/GYN group in Chicago is splitting up, as three senior partners form a new, all-gynecology practice. Obstetric and Gynecologic Specialists of Northwestern has seven female doctors who currently serve more than 25,000 patients. Its founder, Lauren Streicher, MD, initiated the shift to a gynecology-only practice. The four remaining physicians are forming a new OB/GYN group in a new location.