Meet the Team

Connect with our team

John A. Whitfield, M.D.

Principal Investigator

John A. Whitfield, MD, brings more than three decades of exceptional gynecological healthcare training and experience to women in the Fort Worth, Texas area.  After graduating from the University of Missouri-Kansas City I relocated to Dallas for a residency in Obstetrics and Gynecology at Parkland Memorial Hospital.  Dr. Whitfield has had a successful private practice for over 30 years and has been involved in clinical research for 

Zenia Razis

Site Manager

Zenia Razis has been with Dr. Whitfield since June 2021. With over 6 years in healthcare administration and management. 

Randi Oxford


Clinical Research Coordinator

Randi Oxford has been a Clinical Research Coordinator with Signature Gyn Services since January 2022.  A graduate from UTA with a Bachelor’s in psychology.  She has worked in healthcare for over 12 years. 

Tiffani Mbarga

LVN, Clinical Research Coordinator

Tiffani Mbarga has been with Dr. Whitfield since June 2022. With over 7 years as an LVN, she has experience in Pediatrics, Home Health, and Women’s Health.  

Signature Gyn Services Women's Health Clinical Trials Research Studies Fort Worth Texas

Endometriosis Study