For his entire 40+ year research career, Dr. Reynolds has focused on ‘Problems of Pregnancy,’ including infertility, poor pregnancy outcomes and premature birth in livestock. These problems of pregnancy have major socioeconomic and health implications for livestock and for humans as well. Dr. Reynolds is a founding Director of the Center for Nutrition and Pregnancy at NDSU. Along with numerous collaborators throughout the world, he helped establish that placental blood flows are key to normal placental function (i.e., transport between the maternal and fetal systems) throughout gestation. Subsequently, they showed that the placenta produces angiogenic factors, which drive its dramatic vascular development, and were among the first to develop methods to evaluate the rate of cell growth in vivo, including that of the placenta. Dr. Reynolds and co-workers have shown that the profound effects of maternal stressors (e.g., malnutrition) on placental development begin very early in pregnancy, resulting in altered placental function. They also were among the first to recognize and investigate the potential impact and long-term consequences of "developmental programming" in livestock. Currently, Dr. Reynolds and colleagues are investigating therapeutic and management strategies to improve fertility and pregnancy outcomes, as well as the role of the fetal and maternal steroid metabolomes in the processes of fetal organ maturation, birth, and postnatal survival.