Lesley,
When we had our first scan at 12 weeks we were told that bump had one kidney mildly enlarged and that we would need another scan at 28 weeks. When we had our scan at 28 weeks the kidney that was mildly enlarged before was now the smaller of the two kidneys. They put in the report that both bumps kidneys were mildly enlarged at 28 weeks. Dr has not got any real concerns and says this is very common but we will have to have a pediatrician come see bump after he is born to access him and he may need a course of antibiotics soon after birth, and he will need to be checked regularly.

I was the same as you, freaking out and cried thinking I had done something that caused this problem. And when we did our antinatal class a couple of weeks ago the midwife said that in each group there is always at least one couple that has a baby with mildly enlarged kidneys and it very rarely becomes a problem, they just get checked out by the pediatrician. DH and I are certain that bump will be fine but I guess it is always in the back of your mind though.

Most of the time it does sort it self out as the baby grows and if it does need attention its not that bad either. So hang in there and try and enjoy the rest of your pregnancy, more than half way now!