Constipation is normal during pregnancy because the hormones released during pregnancy soothe & relax your body -- including the digestive tract. This means that food digests and processes through your body a lot slower than it did before you got pregnant, and generally causes constipation. It isn't necessarily bad for the baby.
To help with constipation, you can eat lots of high-fiber foods such as beans, fruits and vegetables, whole-grain breads, etc. every day.