A lot of stars also do not gain enough weight during their pregnancy...witness the low birthweights of a lot of their babies. Gwyneth and Kate Hudson excluded, most of these babies being born are barely at the minimum normal weight of 6 lbs.
And I still had a few extra pounds, but that was what I gained back. It took me 9 months to lose the baby weight, and the last three months of that were pretty intense diet and everyday aerobics that I gave up as soon as the scale dropped, then I couldn't be bothered to take it back up again. (Of course, if I'd had a nanny so I could exercise and sleep and a personal trainer and dietician, it might have happened a lot faster!)
I also gained 60 lbs. in that pregnancy, because I had an appetite you wouldn't believe...so it was hard for me to cut my eating back. Whereas this time I hardly even want to eat.