I agree with the first comment ^^^
And the second comment is correct... you retain a lot of water when pregnant! Which explains weight gain.
Kind of depends on what you're eating and how active you are. Also, a lot of it is water weight I think.
Well for one you have a growing baby in you! And I've read the placenta is like two pounds your boobs weigh like two pounds each cause of tissue lol so random I was in such shock when I read that there's other things too but I forgot lol