I dont know about weight loss following second, third, however many pregnancies YET, lol, but I know I had trouble losing my weight from Krue (my first) I wasnt breast feeding and I am hovering at about 2KG more at 11 weeks pregnant then I was at 12 weeks with Krue because of this.
I have heard that it is harder to regain your pre-pregnancy shape after the second baby though from my mum, who said you gain weight faster for a second.

I think that all people have different experiences. I did not experience any extra trouble losing  weight with my subsequent children. I think most people would agree that the trouble some women experience losing weight with extra children is due to a number of factors: 1. Our metabolism slows as we age and 2. The more children we have the more tired we are and therefore the more difficult it is to find the energy and time to lose weight!!!!