Dr Robert Resnik, Professor and Chair Emeritus at the University of California–San Diego (UCSD), has made seminal contributions to the understanding of the physiology of uterine blood flow with the implementation of state-of-the-art experimental techniques. Throughout his career, his work has provided insights into the role of estrogens in increasing uterine blood flow and into the effects of environmental factors, such as nicotine and cocaine, in the regulation of the uterine circulation. His clinical studies on the frequency of white matter lesions in the fetal brain contributed to the identification of fetal injury as a cause for the neurodevelopmental disorders observed in children born preterm and for the role of intra-amniotic infection and vascular anastomosis in monozygotic twins. Dr Resnik is recognized herein as a Giant in Obstetrics and Gynecology.