I didn't know about the US connotation, but it's not an issue here. I'm inclined not to have a nickname for Jemima at all. The one big mistake I made with Theodora was starting the nickname Theo. I changed my mind and don't really use it now, but hubby only calls her Theo, so he introduces her to everyone as Theo, so now no one apart from me, mum and gran actually call her Theodora :(
I'm so insanely excited for my friend. We both started trying for a baby around the same time and Theodora's now 16 months old. Now i'm really hoping that I end up getting pregnant soon so our babies will be close in age!