First pregnancy, 5'1.75", prepregnancy weight 104-108, due late Oct / early Nov:

1st trimester: I ate a maintenance (1300 kcal), stopped exercising and gained about 10 lbs
2nd trimester: I increased to 1500 kcal around 24 weeks and started walking 30-45 min daily, gained no weight. Baby growing well.
3rd trimester: I just increased to 1750 kcal today because I'm getting hungrier and that's what the calculator suggested. I've gained another 4 lbs in the last week or two. Still measuring right on (29cm at 29 weeks) with good fetal movement.