by caryn (10124 Posts), Tue Feb 18, 2014 10:14 pm
HELLP does not require high blood pressure, although I think it must be happening in the smaller vessels or we wouldn't see the hemolysis. (Hemolysis is when the red blood cells are being ripped apart as they're pushed through the smaller vessels by the force of each pump of the heart; it happens when those smaller vessels are very constricted, which is something that happens with hypertension. Maybe the hypertension just hasn't made it to the larger vessels yet...)
They're classed as "hypertensive pregnancy diseases" right now but there's talk of changing the formal terminology to "placental diseases" - hypertension's just a symptom, and it doesn't have to show up.