VTE in pregnancy

Pregnancy is a Factory Slowing Its Safety Valve

Imagine a factory with a fast-moving assembly line (your leg veins carrying blood back to the heart). The factory deliberately makes its lubricating oil (blood) thicker and stickier on purpose — because soon there will be a messy break (delivery bleeding) and thick oil stops leaks better than thin oil. At the same time, a heavy storage crate (the growing uterus) gets placed on top of the main oil return pipe (the iliac veins), slowing the flow to a crawl. The pipe walls also get relaxed and softer (from pregnancy hormones). Now you have sticky oil + slow flow + soft pipe walls — the perfect recipe for a clog (clot) to form inside the pipe even though nothing is broken. If a chunk of that clog breaks off and floats into the air intake filter (the pulmonary arteries in your lungs), the whole system chokes because no fresh air (oxygenated blood) reaches the engine (body tissues).