The most common cause of renal artery stenosis is atherosclerosis, the same condition that causes narrowing of the arteries in coronary heart disease and stroke, and the risk factors are the same as well. Cholesterol plaques build up along the walls of the renal artery and gradually cause narrowing.
Oxytocin is a commonly used uterotonic that can cause significant and even fatal hypotension, particularly when given as a bolus. The resulting hypotension can be produced by a decrease in systemic vascular resistance or cardiac output through a decrease in venous return.
Oxytocin causes smooth muscle contraction associated with the uterus. Utâ¦erine contraction in turn causes the release of more Oxytocin from the pituitary, which causes more contraction. this represents a positive feedback loop of increasing amounts of Oxytocin and uterine contraction. Contractions of the uterus of course result in the movement of the fetus out of the birth canal (leaving the uterus, passing through the cervix, and out through the vaginal opening.