If you are not pregnant, to dream of having a baby can symbolize the birth of a new attitude or viewpoint; new project; new recognition or acceptance of your inner child. It can also refer to separating from some recent relationship; release from an old relations; anticipation of a new future. If you dream of your actual child, it may indicate a wish to return to earlier times (and the reactivation of whatever feelings you have about those times); to go back and change the past; a wish that you still had that kind of power or control over your child.
Birth may also be expressed in dreams symbolically as going in and out of holes, caves, or tunnels; swimming, boating, or otherwise navigating through narrow canals.
If you are pregnant, birthing dreams are typical through your pregnancy and may reflect anxiety about your readiness to be a mother. During the third trimester they may serve to actually make your delivery easier.