It's not really unreasonable, more nosey.
I'm 29 +4 and have only gained half a stone on my pre-pregnancy weight. Approx 1 stone in total as I lost half a stone in the first trimester with morning sickness.
I'm starting to feel unnerved with this weight gain as even though my midwife said everything is on track, quite a few people have commented on how small I still am for how far gone I am.
So just to calm my crazy hormones a bit, can I asked what you gained in your first pregnancy?