Is asking a pregnant woman how much weight she has gained fair game or rude?

We had a picnic tonight for DH's job, and a woman I had never met before asked me how much weight I'd gained during my pregnancy. I told her that I don't look at the scale at my doctor's office and that I track my diet for my childbirth instructor and rely on my doctor or my instructor to inform me if I'm off track because I'm sensitive about it. So the woman presses on and says I need to know how much I've gained so I know how hard I have to work after the baby is born... and then she asks me if I've already got a plan in place for losing the weight.

I thought it was weird and rude...but I'm also super sensitive about my weight gain. DH thought it was a normal question someone would ask a pregnant woman. Settle this... rude or normal?