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.
The most important side effect of rapid injection of oxytocin prior to delivery is tetanic uterine contraction which can result in fetal death and/or uterine rupture. In the postpartum state, the most important potential side effect of intravenous oxytocin bolus is hypotension. Tetanic contractions often lasting several minutes and a sharp decrease in blood pressure have been described following as little as 5 units of oxytocin bolus.