Pre-eclampsia is a strange name for an even stranger illness. While our awareness of this fairly common pregnancy complication dates back to ancient times, our understanding is far from complete.We know it affects women in the second half of pregnancy but we don't know why some get it and others don't.We recognise the main signs and symptoms but we don't know what causes them. And because the cause remains a mystery we have no reliable ways to stop women getting it or cure them (except by delivery) once they have it.We think of it as one disease, but actually it could be several different...