Holding your bump in as much as possible will not harm or squash your baby at all. It will also provide you with the benefit of keeping your abdominal muscles toned, and, probably more importantly, help to prevent backache as your pregnancy progresses. Because of a combination of a changing centre of gravity as your abdomen grows and hormonal changes that soften ligaments, it is normal to find that you are inclined to hollow your lower back, while sticking out the bump, and this can put a great deal of strain on the back. As the pregnancy continues, it will probably get more and more difficult to rely on pulling your abdominal muscles inwards in order to hold your bump in. At this point you could try using a pelvic tilt to have the same effect. This involves standing tall and tucking your bottom under you. If you are able to keep your abdominal muscles toned, this may also help you to get your shape back more quickly after you have given birth. As far as exercising goes, while pregnancy is not the time to begin new vigorous exercise, it is worth continuing with any exercises that you have been doing for as long as possible. As the pregnancy goes on, intense abdominal exercise is best avoided, though.