I'm another one who had a smaller second bub too - first was over 9lb and my second was 8lb 8. it isn't unusual to have a smaller second baby either - I was actually told at my booking appointment at the hospital when we were joking about the possible size considering my first was a big bub and she said that if it was another boy, it was likely to be bigger, but if it was a girl then it could well be smaller. But none of that is set in concrete, just the way things can be sometimes. I'm sure your baby will be born at a size they are meant to be.