Abstract Cannabis use in pregnancy is associated with adverse perinatal outcomes, which are likely mediated by the placenta. However, the underlying mechanisms and specific vasoactive effects of cannabis on the placenta are unknown. Our objective was to determine the impact of chronic prenatal delta-tetrahydrocannabinol (THC, main psychoactive component of cannabis) exposure on placental function and development in a rhesus macaque model using advanced imaging. Animals were divided into two groups, control (CON, n = 5) and THC-exposed (THC, n = 5). THC-exposed animals received a THC edible daily pre-conception and throughout pregnancy. Animals underwent serial ultrasound and MRI at gestational days 85 (G85), G110, G135 and G155 (full...