Thanks Ginny. I did ask a few times in hospital and they said that most likely to just be bad luck. Because of my successful pregnancies they won't look into it any further. At the u/s I had the same sonographer that diagnosed the umbilical herniation but she stressed that that had righted itself and she could see no cause at all. I'm trying to think of it as nature knows best but the 'wonder ifs' are pretty hard to stop.