I'm 5'1" and I was a small frame before pregnancy. I was working out and I am a healthy person. So far I have gain 23lbs and I'm on my 3rd trimester now. Like @Angier017 said there's nothing that we can do about our weight because the baby needs it and we need it to be able to carry our babies for those 9months. Trust me I'm trying to gain only what my doctor recommended me which about 35 to 40 pounds. Try to eat 5 small meals throughout the day and if you are in your 3rd trimester it should be 6 small meals. Try not to eat as much fast food so you don't retain much water weight and your ankles dint get swollen because of the high sodium (salt) that those food have in them.
I only gained about 15 pounds my first and second trimester. Then when third trimester came along... it is really hard to keep the weight off no matter how good ive been eating. If you were small to begin with if you end up gaining 40 lbs thats probably not that bad. And eat more than just a sandwich dear, you and your baby needs more nutrition than that.
Well Im 5'4 and only weighed 113lbs when I found out I was preg. And I have gained about 1lb per week and before I found out I was preg. I ate maybe one "meal" per day (usually a sandwhich)
Pregnant with my second im in my second trimester and haven't gained anything any doctor will tell you that you need to learn to only eat for one not like your starving for 2 the more weight you put on is the cause of big babies and more c sections
I didn't gain any weight my first trimester but now that I'm in my second my weight gain has picked up quite a bit.