I don't know if there is a specific weight that means a baby is IUGR, it is more a conclusion that is drawn from information like ultrasounds, and is often caused by other issues, PE, cord issues, placenta issues etc. I don't know the reason for DD2s IUGR (which can be the case, just one of the mysteries of pregnancy) but her measurements show two different paths, growing happily for the first half then very different from 20 weeks. She was born much smaller than her 'genetic potential' as they say where as DD1 with the same genetic potential was born much larger, all pointing to something being a bit amiss.
