I had one when I was born (well I think it may have been several small ones). Mum never had an ultrasound in her day so it wasn't picked up before I was born, only after I was born and they could hear a heart murmur. She had a normal delivery but not sure if things would have been different if they were aware of it?? I never had to have it operated on (though I did have something else in my heart operated on as a baby) and it just fixed itself and now my cardiologist says my heart is perfect I don't know heaps about VSDs but of the babies that I do know that have had them, all of them have just been left and they have closed over at some point and the heart is perfectly fine.
I think it is a bit hard for Drs to give much information about VSDs before birth because at that point the heart isn't working in it's normal capacity (i.e. not getting oxygen from the lungs so not doing the normal 4 chamber business) but once they baby is born and they take their first breath and the heart and lungs are doing their stuff, then the issue (or non issue as the case may be) is more easily identified.
Good luck.....x