No It won't, I've asked my doctor this when I was In my first trimester and she was tellin' me what symptoms to expect and she said It won't do anythin' to the baby. Thankfully, I haven't had constipation yet, whew. She told me If It happens, to eat plenty of high fiber foods and drink plenty of fluids. Whole-grains, fresh/dried fruits, vegetables, beans, and peas will do the trick (although I haven't had It happen to me, I'm not entirely sure If It works).