Prime Patient Portal


Our Providers:

Our three board certified physicians and Ob nurse practitioner have years of experience in the field of obstetrics and gynecology, and are dedicated to providing the highest quality of care to each patient at Charles Street Ob/Gyn Associates. Click on each name to learn a little more about each one of us!

Robert E. Ottenritter, M.D.
Onkar N. Singh, M.D.
Laura M. Erdman, M.D.
Deb Spinner, CRNP

Provider Name: Robert Ottenritter, MD

Biography: Dr. Ottenritter is a native of the Baltimore area. He received his B.S. from Washington and Lee University and earned his M.D. from the University of Guadalajara. He completed his residency at both the University of Maryland and Maryland General Hospitals in 1987. He then joined the practice of Drs. Haws, Dudley, Morris and Spencer-Strong which had been established in 1933. The practice was later renamed Charles Street Ob/Gyn Associates, and Dr. Ottenritter is currently the president of the practice.

Dr. Ottenritter is board certified and has been a Diplomate of the American Board of Obstetrics & Gynecology since 1989. He is a Fellow in the American College of Obstetricians and Gynecologists. He is currently a member of MedChi, the Baltimore Medical Society, the American Fertility Society, the American College of Physician Executives, and the Delmarva Foundation where he serves as a physician advisor. Dr. Ottenritter is also a member of the century-old Medical and Surgical Club of Baltimore.

Dr. Ottenritter is married and has two children. He is a member of the Baltimore Country Club and the Amelia Island Plantation Club.

Provider Name: Onkar Nath Singh, MD

Biography:Dr. Singh received his M.D. from the world-renowned Prince of Wales Medical College in Patna, India in 1971. He began his residency training in India, and completed his training at Greater Baltimore Medical Center and Union Memorial Hospital in 1981. He was deeply involved in the training and development of residents at Union Memorial until 2000, and has been in private practice since 1981.

Dr. Singh has delivered more than 4,000 babies in his career. He has special interests in high risk obstetrics, minimally invasive surgery, and hysteroscopic surgery. His publications have been published in the Journal of Reproductive Medicine. He is a Diplomate of the American Board of Obstetrics and Gynecology, and is a member of bothe the American College of Obstetricians and Gynecologists and the Maryland Medical Chirurgical Society.

Provider Name: Laura Maciel Erdman, MD

Biography:Dr. Erdman was born in Mexico and grew up in northern New Jersey. She received her B.S. in Chemical Engineering in 1993 from Princeton University in Princeton, N.J., and earned her M.D. in 1997 from Cornell University Medical College in New York City. She completed her residency in Obstetrics & Gynecology at Baylor College of Medicine in Houston, TX in 2001, serving as administrative chief resident during her fourth year. She joined the faculty at Baylor following graduation as an Assistant Professor of Ob/Gyn. After moving to Baltimore County in 2003, Dr. Erdman spent two years at an inner-city not-for-profit community health center, providing obstetric and gynecologic care to an underserved, Hispanic population. She also was appointed to the voluntary teaching faculty at Johns Hopkins School of Medicine, and currently retains that appointment. Dr. Erdman joined Charles Street Ob/Gyn Associates in January of 2006.

Dr. Erdman is board certified and has been a Diplomate of the American Board of Obstetrics & Gynecology since 2003. She is a Fellow in the American College of Obstetricians and Gynecologists, and a member of MedChi, the Maryland Medical Society.

Dr. Erdman is married and has four children.

Provider Name: Deb Spinner, CRNP

Biography: Deb was born in Baltimore and raised in Baltimore and the surrounding area. She received her Bachelor of Science in Nursing from University of Maryland in 1986. She was employed by Johns Hopkins Hospital for thirteen years, working in a general surgical unit, Labor and Delivery and a Post Anesthesia Care Unit. While working at Johns Hopkins, she also worked part-time with nursing agencies in the medical and surgical arenas, private duty nursing and office nursing with a focus on family centered medicine. Following her tenure at Hopkins, Deb was employed at York Hospital's Labor and Delivery for four and a half years. In 2001, she received her Master of Science degree at University of Maryland. She is certified as a Nurse Practitioner in both Adult and Women's Health. She has taught the undergraduate students at University of Maryland in the Clinical Simulation Labs and functioned as a Clinical Instructor in Maternal/Child Health. Deb was a Nurse Practitioner on GBMC's Labor and Delivery Suite for the last ten years, caring for thousands of patients. With over twenty five years of experience in the medical field, Deb is pleased to provide obstetric and gynecologic care to the patients in our practice.

Office Staff

Dianne Cavolo - Office Manager, Surgery Coordinator
Arlene Derr - Front Desk Receptionist
Susan Sunday - Medical Assistant
Janet Sasser - Ultrasonographer
Jamie Russo - Medical Assistant
Ann Langkam - Office Staff
Mary Williams - Insurance Coordinator
Emily Gischel - Billing Coordinator
Jamie Bond - Checkout Receptionist
Shannon Williams - Telephone Receptionist
Stephanie Fetsch - Medical Assistant