Hi Jess,
about bd foods you can google listeria and find out what foods can be unsafe.. if thats wht you meant?
Not sure about how many ultrasounds are wrong but I think the person doing the ultrasound would be able to say something like "i'm 90% sure its a girl" or whatever..
My daughter was in a size 00000 when she was born and wore this size for a few weeks. When I asked in the baby shop they told me to get 000 for a newborn, but that would have been massive on her as she is only now in 000 at almost 6 months. So I guess 0000 would usully fit a newborn too.

hope that helps?